loofah vs luffa

loofah and luffa both are nouns.

Word	Noun	Adjective	Verb	Adverb
loofah	Yes	No	No	No
luffa	Yes	No	No	No

As nouns, luffa is a hypernym of loofah; that is, luffa is a word with a broader meaning than loofah:

loofah: the loofah climber that has cylindrical fruit
luffa: any of several tropical annual climbers having large yellow flowers and edible young fruits; grown commercially for the mature fruit's dried fibrous interior that is used as a sponge

Other hypernyms of loofah include dishcloth gourd, rag gourd, sponge gourd, strainer vine.

As nouns, loofah and luffa are synonyms defined as:

loofah and luffa: the dried fibrous part of the fruit of a plant of the genus Luffa; used as a washing sponge or strainer

Other synonyms of loofah include loofa, loufah sponge.

loofah (noun)	luffa (noun)
the loofah climber that has cylindrical fruit	any of several tropical annual climbers having large yellow flowers and edible young fruits; grown commercially for the mature fruit's dried fibrous interior that is used as a sponge
the dried fibrous part of the fruit of a plant of the genus Luffa; used as a washing sponge or strainer	the dried fibrous part of the fruit of a plant of the genus Luffa; used as a washing sponge or strainer