To be very grig-like, to be merry and full of fun
Sandra sure looks grigful today! I wonder if something good happened lately
noun
An annoying person, adjective/adverb “grigged up”
Caolan: How annoying is that teacher?
Sam: I know, he’s such a grig.
An annoyance and something that is bad or someone who is annoyingly arrogant
That person is being a grig