More leave X, trajectory being partial (5)
I believe the answer is:
extra
'more' is the definition.
(I've seen this in other clues)
'leave x trajectory being partial' is the wordplay.
'being partial' says the answer is hidden in the clue.
'EXTRA' is hidden in the letters of 'leave x trajectory'.
(Other definitions for extra that I've seen before include "Wide, no-ball, leg bye, etc" , "(Theatrical) spear carrier" , "Spare" , "An additional thing" , "someone acting in a crowd" .)