The French get gun out in sudden move (5)
I believe the answer is:
lunge
'sudden move' is the definition.
'lunge' can be an answer for 'move' (lunge is a kind of move). I am unsure of the 'sudden' bit.
'the french get gun out' is the wordplay.
'the french' becomes 'le' ('the' in French).
'get' is an insertion indicator.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'gun' anagrammed gives 'ung'.
'le' enclosing 'ung' is 'LUNGE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for lunge that I've seen before include "(Make a) forward thrust" , "Thrust forward as in fencing" , "Fall upon" , "Charge" , "Sudden forward movement" .)