구만 하다

realize it and say so

-구만, also written -구먼, is the ending for a realization you voice to yourself: ah, so that's how it is. 하다 after it quotes that thought. All five lines here are a speaker voicing an inner reaction and moving straight on — ah, that one's mine too; ah, I finally got my revenge; ah, a paper tiger. It has a blunt, folksy feel rather than a polite one.

Register: informal, folksy