clay vs mud pie

clay and mud pie both are nouns.

Word	Noun	Adjective	Verb	Adverb
clay	Yes	No	No	No
mud pie	Yes	No	No	No

As nouns, mud pie is a hyponym of clay; that is, mud pie is a word with a more specific, narrower meaning than clay:

Other hyponyms of clay include bleaching clay, bleaching earth, mire, slop.

clay (noun)	mud pie (noun)
the dead body of a human being	a mass of mud that a child has molded into the shape of pie
a very fine-grained soil that is plastic when moist but hard when fired
water soaked soil; soft wet earth