Agreed to probe machine-gun requiring repair (6)
I believe the answer is:
broken
'requiring repair' is the definition.
I can't judge whether this definition defines the answer.
'agreed to probe machine-gun' is the wordplay.
'agreed' becomes 'ok' (eg when responding to an offer).
'to probe' means one lot of letters goes inside another (probe can mean to poke or prod into).
'machine-gun' becomes 'bren' (I've seen this before).
'ok' inserted into 'bren' is 'BROKEN'.
Can you help me to learn more?
(Other definitions for broken that I've seen before include "faulty" , "If it's not ..., don't fix it" , "Fractured, damaged" , "Interrupted; smashed" , "Smashed, in pieces" .)