Feeling nauseous, no question, but relaxed (4)
I believe the answer is:
easy
'relaxed' is the definition.
('easy' is associated in meaning with 'relaxed')
'feeling nauseous no question' is the wordplay.
'feeling nauseous' becomes 'queasy' (I've seen this before).
'no' suggests deleting specific letters.
'question' becomes 'qu'.
'queasy' with 'qu' taken out is 'EASY'.
'but' is the link.
(Other definitions for easy that I've seen before include "in plentiful supply" , "... Rider (film)" , "Gentle - light" , "Simply achieved" , "Presenting no problems" .)