rocking horse vs hobbyhorse

rocking horse and hobbyhorse both are nouns.

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

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

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

Other synonyms of rocking horse include hobby.

rocking horse (noun)	hobbyhorse (noun)
a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride	a child's plaything consisting of an imitation horse mounted on rockers; the child straddles it and pretends to ride
	a topic to which one constantly reverts