# unable

/əˈneɪbəɫ/ (US) · /ʌnˈeɪbəl/ (UK)

Source: https://englishreference.com/word/unable
Updated: 2026-06-19

## Senses

### 1. not capable

adjective · CEFR B1

not able to do something because you do not have the skill, time, or power.

For teachers: 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).

### 2. aviation refusal

interjection · CEFR C1 · Technical

a word pilots use to tell air traffic control they cannot follow an order.

For teachers: 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.

## Examples

- She is unable to attend the meeting today.
- The pilot was unable to land the plane because of the thick fog covering the runway.
- Despite several attempts to restart the server, the technical team remained unable to restore the database before the morning shift began.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.