Entering a building for fruit (9)
I believe the answer is:
tangerine
'fruit' is the definition.
(tangerine is a kind of fruit)
'entering a building' is the wordplay.
'building' is an anagram indicator.
'entering'+'a'='enteringa'
'enteringa' with letters rearranged gives 'TANGERINE'.
'for' is the link.
(Other definitions for tangerine that I've seen before include "Orange-type fruit" , "shade" , "something juicy being given to press" , "Variety of mandarin orange" , "Small orange" .)