Soundly recognises the feature (4)
I believe the answer is:
nose
'the feature' is the definition.
(I've seen this in other clues)
'soundly recognises' is the wordplay.
'soundly' indicates a 'sounds like' (homophone) clue.
'recognises' becomes 'knows' ('know' can be a synonym of 'recognize').
'knows' sounds like 'NOSE'.
(Other definitions for nose that I've seen before include "Flair (for wine)" , "Organ of smell" , "blow it!" , "It detects by smell" , "Schnozzle" .)