Silence covering revelation of resignation (5)
I believe the answer is:
shrug
'revelation of resignation' is the definition.
(gesture indicating acceptance or resignation)
'silence covering' is the wordplay.
'silence' becomes 'sh' ('sh' is said to tell someone to be silent).
'covering' becomes 'rug' (rug is a kind of covering).
'sh'+'rug'='SHRUG'
(Other definitions for shrug that I've seen before include "Show lack of concern" , "Shoulder gesture" , "Raise (shoulders) slightly" , "woolly" , "Expressive movement of shoulders" .)