hobby vs rocking horse

hobby and rocking horse both are nouns.

Word	Noun	Adjective	Verb	Adverb
hobby	Yes	No	No	No
rocking horse	Yes	No	No	No

As nouns, hobby and rocking horse are synonyms defined as:

hobby and rocking horse: a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride

Other synonyms of hobby include hobbyhorse.

hobby (noun)	rocking horse (noun)
an auxiliary activity	a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride
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