# tireless

/ˈtaɪɝɫəs/ (US) · /tˈaɪələs/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/tireless
Updated: 2026-05-11

## Definition

having a lot of energy and never seeming to get bored or stop working. You use this to describe someone who works very hard for a long time.

For teachers: characterised by having or showing great effort and energy without becoming exhausted. Often used to describe people dedicated to a specific cause or task.

## Examples

- She is a tireless worker who stays late every night.
- The charity owes its success to the tireless efforts of its volunteers over the last decade.
- Despite his advancing age, the senator remained a tireless advocate for environmental reform, attending every committee meeting and drafting dozens of new proposals.

## Usage notes

- Typically used attributively before a noun like 'effort', 'worker', or 'advocate'.

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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.