hobby vs by-line

hobby and by-line both are nouns.

Word	Noun	Adjective	Verb	Adverb
hobby	Yes	No	No	No
by-line	Yes	No	No	No

As nouns, hobby and by-line are synonyms defined as:

Other synonyms of hobby include avocation, pursuit, sideline, spare-time activity.

hobby (noun)	by-line (noun)
an auxiliary activity	an auxiliary activity
small Old World falcon formerly trained and flown at small birds	a line giving the name of the writer of a story or article
a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride