Lock-up local Marxist briefly for starting trouble (6)
I believe the answer is:
commit
'lock' is the definition.
(thesaurus)
'marxist briefly for starting trouble' is the wordplay.
'marxist' becomes 'com'.
'briefly' becomes 'mi' (I can't justify this - if you can you should give a lot more credence to this answer).
'for' means one lot of letters go next to another.
'starting' suggests taking the first letters.
The first letter of 'trouble' is 't'.
'com'+'mi'+'t'='COMMIT'
'up local' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for commit that I've seen before include "Entrust; pledge (oneself)" , "Confine" , "Do or perform, say a crime" , "Perpetrate, carry out (a crime)" , "Entrust; carry out" .)