Mo's ploy to abandon run (4)
I believe the answer is:
tick
'mo's' is the definition.
(both can mean a short amount of time)
'ploy to abandon run' is the wordplay.
'ploy' becomes 'trick' (I've seen this before).
'to abandon' suggests deleting specific letters.
'run' becomes 'r' (cricket abbreviation).
'trick' with 'r' taken away is 'TICK'.
(Other definitions for tick that I've seen before include "which is irritating!" , "Little bloodsucker" , "credit > check" , "Credit (slang)" , "Objectionable person" .)