OET Writing Vocabulary List: Language Criterion Guide

If your OET Writing Language criterion is weak, the problem is often not a lack of English words, but the wrong words, used in the wrong place, or in the wrong tone. In OET, the highest-scoring letters sound controlled, precise, and professional rather than “fancy”. This guide gives you an OET writing vocabulary list organised by function so you can choose language that helps clarity, accuracy, and tone. It also explains where vocabulary can be overused, especially in advice letters, where simplicity is often stronger than advanced wording.

Why vocabulary matters for the Language criterion

In OET Writing, vocabulary is assessed as part of Language, but not in isolation. Markers look for whether your word choice is accurate, appropriate to the task, and natural for professional communication. Many weaker candidates lose marks because they either repeat basic words too often or attempt to sound formal with uncommon expressions that do not fit clinical English. For example, writing “the patient was suffering from extreme pain in the abdomen” is less effective than “the patient reported severe abdominal pain.” The second version is shorter, clearer, and more professional.

The aim is not to use difficult vocabulary. It is to use the right vocabulary. In clinical writing, “right” usually means concise, standard, and unambiguous. If you write for the patient’s future care team, every word should help the reader understand the problem quickly. That is why a functional vocabulary list is more useful than a long general word bank. It teaches you how to describe symptoms, severity, duration, diagnosis, treatment, and recommendations with accuracy and control.

Symptoms: choose clinical, not dramatic wording

Symptoms should be written in a neutral, factual way. Avoid emotional language, exaggerated phrases, or lay expressions that sound like spoken conversation. The professional form is often shorter and more specific. For example, “feels dizzy” can become “reports dizziness”; “has trouble breathing” becomes “reports dyspnoea” or “shortness of breath”, depending on the register and your familiarity with accepted wording. Similarly, “bad stomach pain” is better as “abdominal pain” or “epigastric pain” if the case supports that term.

Useful symptom vocabulary includes: nausea, vomiting, dizziness, fatigue, lethargy, dyspnoea, palpitations, abdominal pain, diarrhoea, constipation, rash, pruritus, headache, back pain, dysuria, urinary frequency, and blurred vision. Use only what is relevant to the case. A strong OET letter does not list every possible symptom; it selects the symptoms that matter to the referral or discharge purpose. If you over-describe symptoms, you may lose control of tone and cohesion.

Severity: be precise without exaggeration

Severity words help the reader understand the clinical urgency. Weak candidates often rely on vague intensifiers such as “very”, “really”, or “extremely”, which sound informal and imprecise. A better approach is to use medical or semi-medical descriptors that show control. For example, “very painful” can become “severe pain”; “a bit anxious” can become “mild anxiety”; and “could not walk much” can become “marked mobility limitation”.

Common severity terms include: mild, moderate, severe, significant, marked, intermittent, persistent, progressive, debilitating, and debilitating. You may also use “poorly controlled” for chronic conditions such as asthma or diabetes, if the case information supports it. In addition, comparisons can help when relevant: “worsening over the past week”, “gradually increasing”, or “more frequent episodes”. The key is to avoid empty intensifiers. One accurate severity word is better than two or three vague ones. In OET, precision improves readability and supports a stronger Language score.

Chronicity: show duration and course clearly

Chronicity describes how long a condition has been present and how it has changed over time. This is important because the reader needs to understand whether a problem is acute, chronic, recurrent, or longstanding. Weak writing often says only “for a long time” or “since a while ago”, which sounds vague and informal. Professional writing uses clearer time expressions and course markers.

Useful chronicity language includes: acute, chronic, longstanding, persistent, recurrent, intermittent, recent onset, gradual onset, since, over the past three months, for the last two weeks, and progressively. You can also describe trajectory: “has worsened over the past fortnight”, “has been stable”, “has improved”, or “has had episodic symptoms for several months”. Where appropriate, link the onset to a trigger: “following a fall”, “after starting the new medication”, or “since surgery”. This helps the case flow logically. In OET, chronicity words support cohesion because they help the reader see the timeline of the illness without guessing.

Diagnostic certainty: express probability carefully

Diagnostic certainty is one of the easiest places to sound either too weak or too assertive. In referral and handover letters, you should usually avoid sounding as if you are making a final diagnosis unless the case clearly states it. Instead, use cautious, professional language that shows clinical judgement without overclaiming. For example, “appears consistent with”, “suggests”, “is likely due to”, “raises concern for”, and “may represent” are useful forms of hedging.

Other useful terms include: suspected, probable, possible, differential diagnosis, rule out, confirm, and likely. The degree of certainty must fit the case. If the diagnosis is established, say so directly: “Type 2 diabetes mellitus was diagnosed in 2019.” If it is not established, write “The symptoms are suggestive of gastro-oesophageal reflux disease” rather than stating it as fact. Strong candidates know how to balance certainty and caution. They do not hedge everything, but they also do not overstate uncertain findings. This balance is important for accurate, professional communication.

Treatments: use standard clinical wording

Treatment vocabulary should be functional and conventional. The best OET letters use standard verbs and nouns such as commence, continue, discontinue, prescribe, administer, monitor, review, refer, assess, and advise. These are more appropriate than casual verbs like “give”, “stop”, or “check up on”, especially when a formal record is needed. For example, “The GP commenced amoxicillin” is more professional than “The GP gave antibiotics.”

Useful treatment vocabulary includes: medication, dosage, regimen, compliance, adherence, side effects, trial, taper, physiotherapy, wound care, inhaler, nebuliser, referral, follow-up, and monitoring. Be careful with word choice in patient advice letters. If the letter is meant for the patient, excessively technical treatment vocabulary can reduce clarity. “Continue the inhaler twice daily” is usually better than “maintain the inhalational regimen”. The goal is professional clarity, not complexity. Where the addressee is a clinician, use the clinical term; where the addressee is a patient, use language the patient can understand without losing accuracy.

Closings: keep them polite and purpose-driven

The closing of an OET letter should be brief, courteous, and task-focused. Weak candidates sometimes use closing lines that sound stiff, inflated, or formulaic in a way that does not match the rest of the letter. Strong closings are simple and conventional. Examples include: “Please do not hesitate to contact me if you require further information,” “Thank you for your ongoing care of this patient,” and “I would appreciate your review and management of this case.”

For patient letters, closings should remain respectful and clear: “Please attend your follow-up appointment as arranged” or “If your symptoms worsen, please seek medical attention promptly.” Avoid overly emotional or overly apologetic closings. You are not writing a personal email; you are completing a professional task. A good closing supports tone, reinforces purpose, and avoids unnecessary vocabulary. If the body of the letter is strong, the closing should not introduce new language risks. Keep it short, accurate, and appropriate to the audience.

How to avoid over-vocabulary in advice letters

Advice letters are where many candidates make vocabulary mistakes by trying to sound more advanced than necessary. In these letters, clarity matters more than lexical sophistication. If you write to a patient, avoid dense clinical terminology unless it is essential and understandable. For example, “cease smoking immediately” may be too formal if “stop smoking” is clearer for the patient. Likewise, “consume a balanced diet” may sound unnatural when “eat a balanced diet” is better.

Over-vocabulary also appears when candidates replace simple, exact words with rare synonyms. This can create awkwardness or even inaccuracy. For example, “ambulate” is not needed when “walk” is clearer. “Edema” is appropriate in a clinician letter, but not every advice letter needs medical terms if the audience is the patient. A strong strategy is to match vocabulary to purpose. In advice letters, choose language that is polite, direct, and easy to follow. Professional writing is not judged by how many unusual words it contains. It is judged by how clearly the message is conveyed.

Weak to professional substitutions for OET writing

Related OET resources

• Language criterion explained
• Vocabulary improver tool
• OET paraphrasing guide
• Examiner correction

A strong OET writing vocabulary list is not a collection of rare words. It is a practical system for choosing the right word for the right function. If you can describe symptoms accurately, express severity and chronicity clearly, hedge diagnosis appropriately, and use standard treatment language, your Writing will sound much more professional. For weak Language candidates, that improvement alone can make a meaningful difference. Focus on clarity, control, and task fit, and your vocabulary will start working for your score rather than against it.