tributary vs confluent

tributary and confluent both are nouns.

Word	Noun	Adjective	Verb	Adverb
tributary	Yes	Yes	No	No
confluent	Yes	Yes	No	No

As nouns, tributary and confluent are synonyms defined as:

Other synonyms of tributary include affluent, feeder.

tributary (noun)	confluent (noun)
a branch that flows into the main stream	a branch that flows into the main stream

tributary (adjective)	confluent (adjective)
tending to bring about; being partly responsible for	flowing together
paying tribute
(of a stream) flowing into a larger stream