/ˈɑː.bɪ.trər.i/ · adjective
arbitrary
tùy tiện, độc đoán — Được quyết định hoặc thực hiện một cách tùy tiện, không dựa trên lý do, quy tắc hay hệ thống rõ ràng.
The upgrade in 5 seconds
the new rule seems random and unfair
the new rule seems arbitrary
No definition. No dictionary. Just the sentence, made better.
Section 02
The Common Mistake
Many IELTS candidates lean on unfair, random and unreasonable.
“Unfair” and “random” are correct — but vague. They describe the feeling of injustice without naming its cause: a decision made without clear reasoning or system.
“Yes — that's exactly how I write, too.”
Section 03
The Better Choice
This is the step from Band 6 to Band 7 — not a harder word, a more precise one.
Section 04
Why It Works
“Unfair” just says a decision feels wrong. “Arbitrary” says it was made without a clear reason or system — based on whim rather than logic. It names the flaw in the process, not just the outcome.
That precision is why it dominates argument and policy essays. It pairs with nouns of rules and judgement (decision, rule, criteria, deadline, restriction) — the exact collocations Band 8 rewards.
Section 05 · The core of the lesson
Upgrade Matrix
Watch one idea climb from Band 6 to Band 9 — same meaning, rising precision.
Many people think the new visa rule is random and unfair.
Correct, but stacking two vague adjectives is weak and repetitive.
Many people think the new visa rule is arbitrary.
Stronger adjective, though the object could be more specific.
Critics argue that the visa eligibility criteria are arbitrary.
Natural collocation + a concrete subject. This is the target.
Critics argue that the visa eligibility criteria are arbitrary, applied inconsistently across different regions.
Developed idea with a consequence clause — fully controlled.
Employees often feel that promotion decisions are unfair.
Fine, but it names the feeling, not the cause.
Employees often feel that promotion decisions are arbitrary.
“Arbitrary decision” is a top-tier academic collocation.
Employees often feel that promotion decisions are arbitrary, based on personal favouritism rather than merit.
Precise and developed — nothing wasted.
Section 06 · Read against the band descriptors
Examiner's Insight
How this word measures up against the public IELTS Writing & Speaking band descriptors — an editorial read, not a real examiner's verdict.
In Writing Task 2, “arbitrary decision” is the kind of phrasing the band descriptors reward — not because the word is rare, but because it names a lack of reasoned basis precisely. It signals control of academic register, not just a bigger vocabulary.
Section 07
Native Radar
Not about grammar — about whether a native speaker would actually say it.
-
Native would naturally say
the court ruled against the arbitrary dismissal of employees
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Native might say
an arbitrary mistake
Arbitrary describes a choice or decision made without reasoned basis, not an accidental error — “careless” fits a mistake better.
-
Native almost never says
her arbitrary talent
Arbitrary carries a critical, negative tone about decisions or rules — it doesn't fit a positive personal quality like talent.
Section 08 · Under 5 minutes
Active Recall
01 Rewrite using arbitrary: “The professor's grading system seems completely random.”
Model answer
The professor's grading system seems arbitrary.
02 Choose the stronger collocation: arbitrary talent / arbitrary rule.
Answer
arbitrary rule — precise and academic.
03 Complete naturally: “Critics say the new visa quota is completely ______, with no clear justification.”
Answer
arbitrary — “an arbitrary quota” is a natural pairing.
Arbitrary means chosen without reason or system —
not just unfair.
If you forget everything else, keep this.
Section 10 · Editorial rating
Examiner Score
Section 11 · The editor closes
Final Verdict
Arbitrary is one of the sharpest critique adjectives in academic English. It is not a rare word you show off — it is the precise word for a decision or rule that lacks a clear, reasoned basis. The moment you write “an arbitrary decision” instead of “an unfair decision,” your argument critiques the process itself, not just how it feels.
Learn it once, pair it with nouns of rules and judgement — decision, rule, criteria, deadline, restriction — and it will sharpen most argument and policy essays you write.
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