Wart uncovered in feline voicebox (6)
I believe the answer is:
larynx
'voicebox' is the definition.
(I've seen this before)
'wart uncovered in feline' is the wordplay.
'uncovered' means to look at the middle letters.
'in' is an insertion indicator.
'feline' becomes 'lynx' (lynx is a kind of feline).
The central letters of 'wart' are 'ar'.
'ar' put inside 'lynx' is 'LARYNX'.
(Other definitions for larynx that I've seen before include "box of cords?" , "Source of squeaks" , "part of pipe" , "Human voice box" , "Site of the vocal cords" .)