love child vs illegitimate child

love child and illegitimate child both are nouns.

Word	Noun	Adjective	Verb	Adverb
love child	Yes	No	No	No
illegitimate child	Yes	No	No	No

As nouns, love child and illegitimate child are synonyms defined as:

love child and illegitimate child: the illegitimate offspring of unmarried parents

Other synonyms of love child include bastard, by-blow, illegitimate, whoreson.

love child (noun)	illegitimate child (noun)
the illegitimate offspring of unmarried parents	the illegitimate offspring of unmarried parents