Fellow in Ulster, loose and relaxing (7)
I believe the answer is:
restful
'relaxing' is the definition.
(I know that relaxing can be written as restful)
'fellow in ulster loose' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'in' means one lot of letters goes inside another.
'loose' indicates anagramming the letters (letters are loosened from their original positions).
'ulster' is an anagram of 'restul'.
'f' going inside 'restul' is 'RESTFUL'.
'and' acts as a link.
(Other definitions for restful that I've seen before include "Quiet, soothing" , "Tranquil - fluster (anag)" , "Calm" , "Still - calming" , "Soothing is required" .)