sweet cassava vs casava

sweet cassava and casava both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet cassava	Yes	No	No	No
casava	Yes	No	No	No

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

sweet cassava: South American plant with roots used as a vegetable and herbage used for stock feed
casava: any of several plants of the genus Manihot having fleshy roots yielding a nutritious starch

Other hypernyms of sweet cassava include cassava.

sweet cassava (noun)	casava (noun)
South American plant with roots used as a vegetable and herbage used for stock feed	any of several plants of the genus Manihot having fleshy roots yielding a nutritious starch