Look for a second good weapon (6)
I believe the answer is:
glance
'look' is the definition.
(I know that glance is a type of look)
'second good weapon' is the wordplay.
'second good' becomes 'g' (abbreviation. I am not sure about the 'second' bit.).
'weapon' becomes 'lance' (lance is a kind of weapon).
'g'+'lance'='GLANCE'
'for a' acts as a link.
Can you help me to learn more?
(Other definitions for glance that I've seen before include "Momentary look" , "A quick sideways look" , "Skim" , "Look quickly at -- cricket stroke" , "Take a quick look" .)