sandpit vs plaything

sandpit and plaything both are nouns.

Word	Noun	Adjective	Verb	Adverb
sandpit	Yes	No	No	No
plaything	Yes	No	No	No

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

sandpit: a plaything consisting of a pile of sand or a box filled with sand for children to play in
plaything: an artifact designed to be played with

Other hypernyms of sandpit include toy.

sandpit (noun)	plaything (noun)
a plaything consisting of a pile of sand or a box filled with sand for children to play in	an artifact designed to be played with
a large pit in sandy ground from which sand is dug