teddy bear vs plaything

teddy bear and plaything both are nouns.

Word	Noun	Adjective	Verb	Adverb
teddy bear	Yes	No	No	No
plaything	Yes	No	No	No

As nouns, plaything is a hypernym of teddy bear; that is, plaything is a word with a broader meaning than teddy bear:

teddy bear: plaything consisting of a child's toy bear (usually plush and stuffed with soft materials)
plaything: an artifact designed to be played with

Other hypernyms of teddy bear include toy.

teddy bear (noun)	plaything (noun)
plaything consisting of a child's toy bear (usually plush and stuffed with soft materials)	an artifact designed to be played with