As nouns the difference between loveliness and unloveliness
is that loveliness is (uncountable) the property of being lovely, of attractiveness, beauty, appearing to be lovable while unloveliness is the state or condition of being unlovely; ugliness.
loveliness
English
Noun
(uncountable) The property of being lovely, of attractiveness, beauty, appearing to be lovable.
(countable) The result of being lovely.
unloveliness
English
Noun
(-)
The state or condition of being unlovely; ugliness.