The crack about height hurt (4)
I believe the answer is:
ache
'hurt' is the definition.
('ache' can be a synonym of 'hurt')
'the crack about height' is the wordplay.
'the crack' becomes 'ace' (I've seen this before).
'about' means one lot of letters goes inside another.
'height' becomes 'h'.
'ace' enclosing 'h' is 'ACHE'.
(Other definitions for ache that I've seen before include "Hanker" , "Persistent dull pain" , "anguish" , "Dull throbbing pain" , "Pine" .)