faecal matter vs faeces

faecal matter and faeces both are nouns.

Word	Noun	Adjective	Verb	Adverb
faecal matter	Yes	No	No	No
faeces	Yes	No	No	No

As nouns, faecal matter and faeces are synonyms defined as:

faecal matter and faeces: solid excretory product evacuated from the bowels

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

faecal matter (noun)	faeces (noun)
solid excretory product evacuated from the bowels	solid excretory product evacuated from the bowels