Brief look at top gun with mediaeval weapon (6)
I believe the answer is:
glance
'brief look' is the definition.
(I've seen this before)
'top gun with mediaeval weapon' is the wordplay.
'top' suggests taking the first letters (in a down clue, the first letter is top).
'with' says to put letters next to each other.
'mediaeval weapon' becomes 'lance' (lance is a kind of weapon. I am not sure about the 'mediaeval' bit.).
The first letter of 'gun' is 'g'.
'g'+'lance'='GLANCE'
'at' acts as a link.
Can you help me to learn more?
(Other definitions for glance that I've seen before include "Look briefly or bounce off" , "black shiny stuff" , "Butcher" , "A dart of the eye" , "batsman's shot" .)