gari vs casava

gari and casava both are nouns.

Word	Noun	Adjective	Verb	Adverb
gari	Yes	No	No	No
casava	Yes	No	No	No

As nouns, casava is a hypernym of gari; that is, casava is a word with a broader meaning than gari:

gari: cassava with long tuberous edible roots and soft brittle stems; used especially to make cassiri (an intoxicating drink) and tapioca
casava: any of several plants of the genus Manihot having fleshy roots yielding a nutritious starch

Other hypernyms of gari include cassava.

gari (noun)	casava (noun)
cassava with long tuberous edible roots and soft brittle stems; used especially to make cassiri (an intoxicating drink) and tapioca	any of several plants of the genus Manihot having fleshy roots yielding a nutritious starch