Sure to use tactic (4)
I believe the answer is:
ruse
'tactic' is the definition.
(I have seen 'Deceptive tactic ' mean 'ruse' so perhaps 'tactic' could also mean 'ruse')
'sure to use' is the wordplay.
'to use' indicates anagramming the letters (I've seen 'used' mean this).
'sure' anagrammed gives 'RUSE'.
(Other definitions for ruse that I've seen before include "Sue to be a ploy" , "Clever stratagem or plan" , "Deceptive device" , "Plan intended to deceive" , "Sure to be a trick" .)