fecal matter vs feces

fecal matter and feces both are nouns.

Word	Noun	Adjective	Verb	Adverb
fecal matter	Yes	No	No	No
feces	Yes	No	No	No

As nouns, fecal matter and feces are synonyms defined as:

fecal matter and feces: solid excretory product evacuated from the bowels

Other synonyms of fecal matter include BM, dejection, faecal matter, faeces, ordure, stool.

fecal matter (noun)	feces (noun)
solid excretory product evacuated from the bowels	solid excretory product evacuated from the bowels