Is that funny? Silence! (3)

I believe the answer is:

gag

I believe this is a double definition.

'is that funny?' is the first definition.
(gag can mean joke)

'silence' is the second definition.
(gagging is a kind of silencing)

(Other definitions for gag that I've seen before include "Make quiet" , "Shut up" , "Stop someone telling" , "Prevent free expression" , "Silence the joke" .)

I've seen this clue in The Times.

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