Pass away in a sleep perhaps (6)
I believe the answer is:
elapse
'pass away' is the definition.
(I've seen this in another clue)
'a sleep perhaps' is the wordplay.
'perhaps' indicates an anagram.
'a'+'sleep'='asleep'
'asleep' is an anagram of 'ELAPSE'.
'in' is the link.
(Other definitions for elapse that I've seen before include "Glide by" , "run by" , "Pass away - asleep (anag)" , "(Of time) go by" , "pass in silence" .)