Smart alec's in clink now, allegedly (4-3)
I believe the answer is:
know-all
'smart alec's' is the definition.
(both can mean an annoyingly clever person)
'in clink now allegedly' is the wordplay.
'in' indicates the answer is hidden within the clue.
'KNOW-ALL' is hidden in the letters of 'clink now allegedly'.
(Other definitions for know-all that I've seen before include "Type of person who wont take advice" , "Self-styled polymath" , "Person who behaves like encyclopedia 94-3)" , "Smart alec" , "One supposedly omniscient" .)