Word
unable
Phoneticsun·able
US/əˈneɪbəɫ/
UK/ʌnˈeɪbəl/
Definitions
01not capable
B1 · Intermediate
adj. not able to do something because you do not have the skill, time, or power.
adj. lacking the necessary power, ability, resources, or opportunity to perform a specific action. Usually followed by a 'to' infinitive.
“She was unable to attend the meeting because her flight was delayed.”
“Despite several attempts to resolve the technical glitch, the support team remained unable to restore the database before the morning shift began.”
Usage
Always used with a following 'to' + infinitive; it is never used as an attributive adjective before a noun (e.g., 'an unable man' is incorrect).
Pitfall
I am unable of coming to the party.
I am unable to come to the party.
The adjective 'unable' must be followed by 'to' and a verb, not 'of' and a gerund.
02aviation refusal
C1 · Advanced Aviation Technical
interj. a word pilots use to tell air traffic control they cannot follow an order.
interj. a standardized radio telephony term used to indicate that a requested maneuver or instruction cannot be safely or legally executed.
“The pilot told the tower 'unable' when asked to climb to a higher altitude.”
“Upon receiving the instruction to expedite the descent, the captain responded with 'unable' due to the severe turbulence reported at lower levels.”
Usage
Used as a standalone response in radio communications.
Teaching tip
This is highly specialized jargon; outside of aviation, using 'unable' as a one-word sentence sounds very abrupt or robotic.
Synonyms
Antonyms
Collocations
Common phrases and expressions where native English speakers use the word “unable” in context.
Verb
01. find unable
“I find myself unable to agree with the proposal in its current form.”
verb + adj
02. unable to attend
“Please accept my apologies as I am unable to attend the meeting tomorrow.”
adj + prep + verb
Adjective
03. physically unable
“He wanted to help with the move, but he was physically unable to lift heavy boxes.”
adv + adj
04. unable to access
05. unable to get
06. unable to confirm
07. unable to read
08. unable to find
09. be utterly unable to
“She was utterly unable to recall where she had left her car keys.”
10. declared unable to
“The athlete was declared unable to play following a failed fitness test.”
11. unable to leave
12. unable to see
Etymology
From Middle English unable, unabel, unhable, unhabil, equivalent to un- + able.
From Middle English unablen, equivalent to un- + able.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
VERB
NOUN
ADJECTIVE
ADVERB
Domain
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B1 PreliminaryIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.4.0–5.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 3.0–3.544–71TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.550–784
- Frequency
- Common
- Level
- B1 · IntermediateOxford
- Updated
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englishreference.com/q/unable