Not all the timber is in court (3)
I believe the answer is:
woo
'court' is the definition.
(both can mean to romance someone)
'not all the timber' is the wordplay.
'not all' means to remove the last letter (not all of the word).
'the timber' becomes 'wood' (I've seen this in another clue).
'wood' with its last letter taken away is 'WOO'.
'is in' acts as a link.
(Other definitions for woo that I've seen before include "Court, seek to marry" , "Court a lady" , "Try to attract" , "Try to get the girl?" , "Court, romance" .)