Spanner

n.

Heard in Limerick, Cork, Sligo, Dublin and Wexford

An affectionate or exasperated term for a foolish, clumsy, or clueless person.

In use

Yer a right spanner you are, droppin de keys down de drain like dat!

Posh English

You are a thoroughly incompetent fellow, dropping the latch keys down the drain in that fashion!

Same phrase, other counties