Lame man's first goal (4)
I believe the answer is:
maim
'lame' is the definition.
(thesaurus)
'man's first goal' is the wordplay.
'man's first' becomes 'm' (ast letter of 'man').
'goal' becomes 'aim' (aim is a kind of goal).
'm'+'aim'='MAIM'
(Other definitions for maim that I've seen before include "Wound and permanently disfigure" , "Cripple, mutilate" , "Wound and cripple" , "Injure and cripple" , "Disable, lame" .)