Idle brutes, if disturbed, played for time (12)
I believe the answer is:
filibustered
'played for time' is the definition.
(I've seen this before)
'idle brutes if disturbed' is the wordplay.
'disturbed' indicates anagramming the letters.
'idle'+'brutes'+'if'='idlebrutesif'
'idlebrutesif' anagrammed gives 'FILIBUSTERED'.
(Other definitions for filibustered that I've seen before include "played for time" , "Deliberately obstructed progress - Tiberius fled (anag)" .)