Blubber when some verbal flak's about (4)
I believe the answer is:
flab
'blubber' is the definition.
(I've seen this in another clue)
'some verbal flak's about' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'about' says the letters should be written in reverse.
'balf' is hidden in the letters of 'verbal flaks'.
'balf' backwards is 'FLAB'.
'when' acts as a link.
(Other definitions for flab that I've seen before include "Sign of overeating" , "Loose body fat" , "Excess fat (colloq.)" , "Unwanted body fat" , "Sign of over-indulgence" .)