concomitant vs accompanying

concomitant is a noun but accompanying is not a noun.

Word	Noun	Adjective	Verb	Adverb
concomitant	Yes	Yes	No	No
accompanying	No	Yes	No	No

As adjectives, concomitant and accompanying are synonyms defined as:

concomitant and accompanying: occurring with or following as a consequence

Other synonyms of concomitant include attendant, collateral, consequent, ensuant, incidental, resultant, sequent.

concomitant (noun)	accompanying (noun)
an event or situation that happens at the same time as or in connection with another

concomitant (adjective)	accompanying (adjective)
occurring with or following as a consequence	occurring with or following as a consequence