Purdy is forced to stop talking (3,2)
I believe the answer is:
dry up
'stop talking' is the definition.
(dry up can mean to run out of things to say)
'purdy is forced' is the wordplay.
'is forced' is an anagram indicator.
'purdy' with letters rearranged gives 'DRY UP'.
'to' is the link.
(Other definitions for dry up that I've seen before include "(Of flow) decrease and stop" , "Shrivel" , "Turn off gas" , "work in kitchen" , "lend a hand in the scullery" .)