# cuckoo

/ˈkəˌku/ (US) · /kˈʊkuː/ (UK)

Source: https://englishreference.com/word/cuckoo
Updated: 2026-08-27

## Senses

### 1. crazy or silly

adjective · CEFR B2 · Informal · Slang

acting in a way that is crazy, strange, or very silly.

For teachers: mentally unbalanced or eccentric. Used as a predicative adjective in informal contexts.

- You must be cuckoo if you think I am going to jump into that freezing water.
- The neighbors thought the old man had gone completely cuckoo when he started painting his entire house bright purple in the middle of the night.

### 2. the bird

noun · CEFR B2

a grey bird that makes a famous two-note sound and lays its eggs in other birds' nests.

For teachers: any bird of the family Cuculidae, noted for its characteristic call and brood parasitism.

- We heard a cuckoo calling from the woods early this morning.
- The common cuckoo is famous for its parasitic behavior, laying its eggs in the nests of smaller songbirds to be raised by unsuspecting foster parents.

### 3. a crazy person

noun · CEFR C1 · Informal · Slang

a person who is acting crazy or strange.

For teachers: a person perceived as insane or highly eccentric.

- Don't listen to him; he's just a bit of a cuckoo.
- The local kids whispered that the hermit was a total cuckoo, though he was actually just a retired professor who enjoyed his privacy.

### 4. to repeat incessantly

verb · CEFR C2 · Literary

to say the same thing over and over again in an annoying way.

For teachers: to repeat a statement or idea incessantly, mimicking the repetitive nature of the bird's call.

- He kept cuckooing the same political slogans all evening.
- The critics cuckooed the same tired complaints about the director's style without offering any fresh analysis of the film itself.

### 5. to take over a home

verb · CEFR C1 · British English · Technical

when criminals take over a vulnerable person's home to use it for illegal activities.

For teachers: to take over the residence of a vulnerable individual to use it as a base for drug dealing or other criminal activity.

- The police are trying to protect elderly residents from being cuckooed by local gangs.
- Authorities have seen a rise in cuckooing, where organized crime groups exploit vulnerable tenants to establish safe houses for distribution.

Usage: Often used in the gerund form 'cuckooing'.

## Examples

- That plan sounds completely cuckoo to me.
- The neighbors thought he had gone cuckoo when they saw him mowing his lawn at three in the morning.
- While the proposal was initially dismissed as cuckoo by the board, it eventually proved to be the only viable solution to the company's mounting debt crisis.

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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.