Use 'cock up' in casual conversation, not in formal writing or speeches.

Colloquial Usage

'Cock up' is primarily British slang, may confuse speakers from other regions.

British Slang

Often used when admitting a mistake or taking responsibility for an error.

Often used to point out a mistake humorously.

Generally not considered offensive but still informal.

Can be used to admit one’s own mistakes without being too serious.

This obsolete meaning is rarely used today but could appear in historical contexts.

Might be encountered in older literature or stylistic writing.

Useful to understand when reading novels set in the past.