fara á kostum

From kostir (“for a horse to trot quickly”), from kostur (“merit”).

fara á kostum

1. to do exceptionally well in some performance (e.g. an actor doing well in a film, or a footballer performing well in a game)

   Hann fór á kostum og skoraði 12 mörk. ― He did absolutely amazingly and scored 12 goals.

• kostulegur

• vera í essinu sínu