Skill in spear throwing (3)
I believe the answer is:
art
'skill' is the definition.
(both can mean a talent)
'in spear throwing' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ART' is hidden in the letters of 'spear throwing'.
(Other definitions for art that I've seen before include "Music, painting etc" , "Drawing" , "-- Garfunkel, singer" , "This gallery displays paintings" , "Skill in a specified thing" .)