Romance has nothing to do with a party atmosphere (4,6)
I believe the answer is:
love affair
'romance' is the definition.
(synonyms)
'nothing to do with a party atmosphere' is the wordplay.
I cannot quite see how this works, but
'nothing' could be 'love' (love means zero in tennis) and 'love' is present in the answer.
'do' could be 'affair' (I've seen this in another clue) and 'affair' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'has' is the link.
Can you help me to learn more?
(Other definitions for love affair that I've seen before include "Romance" , "A (short?) romantic relationship" .)