Trendy doctor, returning gift, is everywhere (11)
I believe the answer is:
omnipresent
'everywhere' is the definition.
(I've seen this in another clue)
'trendy doctor returning gift' is the wordplay.
'trendy' becomes 'in' ('in' can mean fashionable).
'doctor' becomes 'mo' (medical officer).
'returning' is a reversal indicator.
'gift' becomes 'present' (present is a kind of gift).
'in'+'mo'='inmo'
'inmo' backwards is 'omni'.
'omni'+'present'='OMNIPRESENT'
'is' is the link.
(Other definitions for omnipresent that I've seen before include "Constantly encountered" , "Found everywhere" , "travelling all over the place" , "Ubiquitous" , "(Of God) everywhere simultaneously" .)