Bad folk not half getting the bird (4)
I believe the answer is:
ruff
'the bird' is the definition.
(ruff is a kind of bird)
'bad folk not half' is the wordplay.
'bad folk' becomes 'ruffians' (ruffian can mean a violent or criminal person).
'not half' suggests halving the letters.
'ruffians' cut in half is 'RUFF'.
'getting' acts as a link.
(Other definitions for ruff that I've seen before include "Elizabethan or Jacobean neck adornment" , "High tight collar" , "Ring of fur around neck of bird or animal" , "Male sandpiper" , "Fish; neck frill" .)