Go into business half-cut (5)
I believe the answer is:
enter
'go into' is the definition.
(enter can mean to go into a place)
'business half-cut' is the wordplay.
'business' becomes 'enterprise' (enterprise can mean a business).
'half cut' indicates taking half.
'enterprise' with half the letters taken is 'ENTER'.
(Other definitions for enter that I've seen before include "Come in - penetrate - record" , "cross the threshold" , "Enroll, sign up" , "Gain access to" , "Inscribe" .)