Whistle — or miaow? (7)
I believe the answer is:
catcall
I believe this is a double definition.
'whistle' is the first definition.
(I've seen this before)
'miaow?' is the second definition.
(sound made by a cat)
'or' acts as a link.
(Other definitions for catcall that I've seen before include "Express disapproval" , "Shout of derision" , "Audibly disapprove" , "Feline whistle of disapproval" , "taunt from the audience" .)