Money keeps fifty engaged in conflict (5)
I believe the answer is:
clash
'engaged in conflict' is the definition.
'clash' can be an answer for 'conflict' (clash is a kind of conflict). I am not sure about the 'engaged in' bit.
'money keeps fifty' is the wordplay.
'money' becomes 'cash' (cash is a type of money).
'keeps' means one lot of letters goes inside another.
'fifty' becomes 'L' (Roman numeral).
'cash' enclosing 'l' is 'CLASH'.
Can you help me to learn more?
(Other definitions for clash that I've seen before include "Loud noise - conflict" , "Come into violent conflict" , "Conflict, between colours say" , "Forceful disagreement" , "Fail to fit" .)