body waste vs weewee

body waste and weewee both are nouns.

Word	Noun	Adjective	Verb	Adverb
body waste	Yes	No	No	No
weewee	Yes	No	No	No

As nouns, weewee is a hyponym of body waste; that is, weewee is a word with a more specific, narrower meaning than body waste:

body waste: waste matter (as urine or sweat but especially feces) discharged from the body
weewee: liquid excretory product

body waste (noun)	weewee (noun)
waste matter (as urine or sweat but especially feces) discharged from the body	liquid excretory product