It sounds like a fruit tree? Exactly (5)
I believe the answer is:
plumb
'exactly' is the definition.
(I've seen this before)
'it sounds like a fruit tree?' is the wordplay.
'it sounds like' shows a homophone (sound like).
'a fruit tree?' becomes 'plum' (plum is a kind of fruit tree).
'plum' sounds like 'PLUMB'.
(Other definitions for plumb that I've seen before include "Exactly - perpendicular" , "Utterly" , "Measure (water's depth)" , "Vertical; measure (depth)" , "Lead weight; exactly" .)