Poet's right to vanish before becoming amateur crime-fighter (9)
I believe the answer is:
vigilante
'crime-fighter' is the definition.
(I've seen this before)
'poet's right to vanish before becoming amateur' is the wordplay.
I cannot quite see how this works, but
'before' could be 'ante' (prefix meaning before) and 'ante' is found in the answer.
'amateur' could be 'l' (as in a learner driver with L-plates on their car) and 'l' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for vigilante that I've seen before include "Unofficial policeman" , "Unofficial security figure" , "Self-appointed lawman" , "Policeman unofficially" , "One taking the law into his own hands" .)