Make one’s way with purpose (4)
I believe the answer is:
wend
'make one's way' is the definition.
(I've seen this in another clue)
'with purpose' is the wordplay.
'with' becomes 'w' (short for with).
'purpose' becomes 'end' (both can mean a goal).
'w'+'end'='WEND'
(Other definitions for wend that I've seen before include "Slav" , "Make (ones way)" , "Slowly go" , "Travel" , "... one's way, go on a journey" .)