Fierce

n.

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

An intensifier meaning exceptionally or intensely.

In use

Tis fierce cold outside today, you'd want three jumpers on you!

Posh English

The weather outside is remarkably frigid today, one requires three pullovers at the very least.

Same phrase, other counties