Hardly any, you say? What a relief (4)
I believe the answer is:
phew
'what a relief' is the definition.
(I've seen this in other clues)
'hardly any you say?' is the wordplay.
'hardly any' becomes 'few' (similar in meaning).
'you say?' shows a homophone (sound like).
'few' sounds like 'PHEW'.
(Other definitions for phew that I've seen before include "Good gracious, its hot!" , "Sound relieved" , "I'm overheating?" , "thank goodness!" , "Gosh, I'm sweltering!" .)