Don vs river

Don and river both are nouns.

Word	Noun	Adjective	Verb	Adverb
Don	Yes	No	No	No
river	Yes	No	No	No

Don (noun)	river (noun)
a Spanish courtesy title or form of address for men that is prefixed to the forename	a large natural stream of water (larger than a creek)
a European river in southwestern Russia; flows into the Sea of Azov
Celtic goddess; mother of Gwydion and Arianrhod; corresponds to Irish Danu
a Spanish gentleman or nobleman