Allergy sound (5)
'allergy sound' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for wheeze that I've seen before include "Breathe noisily; clever dodge" , "Sound of difficult breathing" , "Breathe hoarsely - it's a clever plan" , "Breathe with difficulty - idea" , "Whistling breath and clever scheme" .)