BM vs fecal matter

BM and fecal matter both are nouns.

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

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

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

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