Nudist endearingly covering belly (7)
I believe the answer is:
distend
'belly' is the definition.
(thesaurus)
'nudist endearingly covering' is the wordplay.
'covering' says the answer is hidden in the clue.
'DISTEND' is hidden in the letters of 'nudist endearingly'.
(Other definitions for distend that I've seen before include "Cause to swell" , "Bloat" , "Exaggerate" , "Swell with internal pressure" , "Fill out" .)