Invalidated cover? (3)
I believe the answer is:
lid
'invalidated cover?' is the definition.
'lid' can be an answer for 'cover?' (lid is a kind of cover). I am not certain of the 'invalidated' bit.
'invalidated cover?' is the wordplay.
'cover?' indicates a hidden word (I've seen 'covering' mean this).
'LID' is hidden in the letters of 'invalidated'.
Can you help me to learn more?
(Other definitions for lid that I've seen before include "Top for pot or jar" , "Covering" , "Hat" , "Cover for box or eye" , "Cap or top for container" .)