마저 + verb (마저 먹다/하다) = finish the rest
(finishing) the rest, completely, all the way
Example
남은 밥을 마저 먹고 나갈게요.
I'll finish the rest of my rice and then go out.
Good to know
As an adverb it means 'finish off the rest'; as a particle (너마저) it means 'even you'.
Related words