love song vs love-song

love song and love-song both are nouns.

Word	Noun	Adjective	Verb	Adverb
love song	Yes	No	No	No
love-song	Yes	No	No	No

As nouns, love song and love-song are synonyms defined as:

love song and love-song: a song about love or expressing love for another person

love song (noun)	love-song (noun)
a song about love or expressing love for another person	a song about love or expressing love for another person