Attack dislodged tons, stifling scream? (9)
I believe the answer is:
onslaught
'attack' is the definition.
(an onslaught is an attack)
'dislodged tons stifling scream?' is the wordplay.
'dislodged' indicates an anagram.
'stifling' means one lot of letters goes inside another.
'scream?' becomes 'laugh' (scream is a kind of laugh).
'tons' anagrammed gives 'onst'.
'onst' enclosing 'laugh' is 'ONSLAUGHT'.
(Other definitions for onslaught that I've seen before include "Barrage" , "Sally" , "Assault" , "Aggressive action" , "Fierce attack" .)