Paroxysm from cast for the audience (5)
I believe the answer is:
throe
'paroxysm' is the definition.
(I've seen this in another clue)
'cast for the audience' is the wordplay.
'cast' becomes 'throw' (synonyms).
'for the audience' shows a homophone (sound like) (how an audience might hear it).
'throw' sounds like 'THROE'.
'from' acts as a link.
(Other definitions for throe that I've seen before include "Convulsion" , "pain" , "Spasm - pang" , "Other (anag.)" .)