pursuit vs hobby

pursuit and hobby both are nouns.

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

As nouns, hobby is a hyponym of pursuit; that is, hobby is a word with a more specific, narrower meaning than pursuit:

pursuit: a diversion that occupies one's time and thoughts (usually pleasantly)
hobby: an auxiliary activity

Other hyponyms of pursuit include avocation, by-line, pursuit, sideline, spare-time activity.

As nouns, pursuit and hobby are synonyms defined as:

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

pursuit (noun)	hobby (noun)
the act of pursuing in an effort to overtake or capture	an auxiliary activity
a diversion that occupies one's time and thoughts (usually pleasantly)	small Old World falcon formerly trained and flown at small birds
an auxiliary activity	a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride
a search for an alternative that meets cognitive criteria