Look briefly good with jousting weapon (6)
I believe the answer is:
glance
'look briefly' is the definition.
(I've seen this before)
'good with jousting weapon' is the wordplay.
'good' becomes 'g' (abbreviation).
'with' is a charade indicator (letters next to each other).
'jousting weapon' becomes 'lance' (I've seen this before).
'g'+'lance'='GLANCE'
(Other definitions for glance that I've seen before include "deflection" , "it has a metallic lustre" , "A passing look." , "oblique movement" , "black shiny stuff" .)