also: いかなくちゃ
I've got to go; I must be going
A set expression meaning 'I must go' or 'I have to leave'. It is a contraction of 行かなくてはならない, with the ending omitted. Used when the speaker feels obliged to depart.
See also: なくては
It's late, so I should be going soon.
Sorry, I have something to do, so I've got to go.
Colloquial contraction, common in casual speech.
Contraction of 行かなくてはならない (must go), with the final part omitted. The なくては pattern expresses obligation.