hula-hoop vs plaything

hula-hoop and plaything both are nouns.

Word	Noun	Adjective	Verb	Adverb
hula-hoop	Yes	No	No	No
plaything	Yes	No	No	No

As nouns, plaything is a hypernym of hula-hoop; that is, plaything is a word with a broader meaning than hula-hoop:

hula-hoop: plaything consisting of a tubular plastic hoop for swinging around the hips
plaything: an artifact designed to be played with

Other hypernyms of hula-hoop include toy.

hula-hoop (noun)	plaything (noun)
plaything consisting of a tubular plastic hoop for swinging around the hips	an artifact designed to be played with