Look! Girl has spear! (6)
I believe the answer is:
glance
'look' is the definition.
(glance is a kind of look)
'girl has spear' is the wordplay.
'girl' becomes 'g'.
'has' means one lot of letters go next to another.
'spear' becomes 'lance' (synonyms).
'g'+'lance'='GLANCE'
(Other definitions for glance that I've seen before include "Batting stroke" , "Butcher's" , "Batsman's stroke" , "Flash" , "Look quickly at -- cricket stroke" .)