by-blow vs love child

by-blow and love child both are nouns.

Word	Noun	Adjective	Verb	Adverb
by-blow	Yes	No	No	No
love child	Yes	No	No	No

As nouns, by-blow and love child are synonyms defined as:

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

by-blow (noun)	love child (noun)
the illegitimate offspring of unmarried parents	the illegitimate offspring of unmarried parents