Any thug could become wayward (7)
I believe the answer is:
naughty
'wayward' is the definition.
(I've seen this before)
'any thug could become' is the wordplay.
'could become' indicates an anagram.
'any'+'thug'='anythug'
'anythug' is an anagram of 'NAUGHTY'.
(Other definitions for naughty that I've seen before include "Badly behaved, mischievous" , "Wicked" , "Badly-behaved" , "Risqu" , "Badly behaved, child say" .)