hobby vs avocation

hobby and avocation both are nouns.

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

As nouns, hobby and avocation are synonyms defined as:

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

hobby (noun)	avocation (noun)
an auxiliary activity	an auxiliary activity
small Old World falcon formerly trained and flown at small birds
a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride