hobby vs sideline

hobby and sideline both are nouns.

Word	Noun	Adjective	Verb	Adverb
hobby	Yes	No	No	No
sideline	Yes	No	Yes	No

As nouns, hobby and sideline are synonyms defined as:

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

hobby (noun)	sideline (noun)
an auxiliary activity	an auxiliary activity
small Old World falcon formerly trained and flown at small birds	an auxiliary line of merchandise
a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride	a line that marks the side boundary of a playing field

hobby (verb)	sideline (verb)
	remove from the center of activity or attention; place into an inferior position