A duck circles entrance to Colwyn Bay
I believe the answer is:
alcove
'bay' is the definition.
(synonyms)
'a duck circles entrance to colwyn' is the wordplay.
'duck' becomes 'love'.
'circles' indicates putting letters inside.
'entrance to' says to take the initial letters.
The first letter of 'colwyn' is 'c'.
'love' placed around 'c' is 'lcove'.
'a'+'lcove'='ALCOVE'
(Other definitions for alcove that I've seen before include "bay" , "Recessed part of a room" , "Recess in a small room or wall" , "sheltered spot" , "Small opening off a larger room" .)