Contraction of -(으)려고 하다가. Expresses that the speaker intended or tried to do something, but the intention was interrupted by something else, leaving the original intention unfulfilled.

• •Interrupted: "가려다가 포기했어요" (I was going to go, but gave up)
• •Change of plans: "먹으려다가 그냥 나왔어요" (I was going to eat, but just left)