Fierce

adv.

Heard in Offaly, Kerry, Leitrim, Cork, Kilkenny, Donegal, Cavan, Mayo, Roscommon, Galway, Meath, Waterford and Kildare

Very or extremely.

In use

I had a skinful last night and now I have a fierce bad hangover.

Posh English

I consumed a considerable quantity of alcohol last night and now I have an extremely unpleasant hangover.

Same phrase, other counties