Shitehawk

n.

Heard in Cork, Wexford, Tipperary and Carlow

A contemptible, untrustworthy person or an absolute idiot.

In use

Don't mind him at all, he's some absolute shitehawk of a feen!

Posh English

Pay him no heed whatsoever, for he is a complete and utter buffoon of a fellow.

Same phrase, other counties