Leave somewhat short (4)
I believe the answer is:
quit
'leave' is the definition.
(I know that quit is a more specific form of leave)
'somewhat short' is the wordplay.
'somewhat' becomes 'quite' (I've seen this before).
'short' means to remove the last letter.
'quite' with its last letter taken off is 'QUIT'.
(Other definitions for quit that I've seen before include "Vacate" , "Give up or abandon a task" , "Cease" , "Pay off (a debt)" , "Leave office" .)