Similar to 든지. Expresses that either one of the two stated actions or situations is acceptable. If there is only one stated action, it can be a suggestion that the listener do the stated action "or something" and is often motivated by anger or passive-aggression. Is sometimes written as "-던가" although this is not standard spelling.
Examples
아, 들으라고 한 소리는 아니구나? 그럼 말소리를 좀 작게 소곤대면서 하<span class='focus'>든가</span>. 아니면 어디 구석에 찌그러져서 지껄이<span class='focus'>든가</span>.
Oh, [what you just said] wasn't meant to be heard? Then maybe you should whisper it. Or squish yourselves into a corner before prattling on.