Crawthumper

n.

Heard in Waterford, Mayo and Dublin

A sanctimonious person who likes to appear holier than thou.

In use

Did you see Mary at mass last sunday, no bigger crawthumper was in the chapel.

Posh English

Did you happen to observe Mary at divine service last Sunday? A more sanctimonious hypocrite never darkened the chapel doors.

Same phrase, other counties