Go in, or go in for (5)

I believe the answer is:

enter

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'go in' is the definition.
(as in entering a building)

I can't explain the rest of the clue.

(Other definitions for enter that I've seen before include "Come or go in" , "A key on the right" , "Enrol" , "Take part in a contest" , "Gain access to" .)

I've seen this clue in The Irish News.

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