spelldown vs competition

spelldown and competition both are nouns.

Word	Noun	Adjective	Verb	Adverb
spelldown	Yes	No	No	No
competition	Yes	No	No	No

As nouns, competition is a hypernym of spelldown; that is, competition is a word with a broader meaning than spelldown:

spelldown: a contest in which you are eliminated if you fail to spell a word correctly
competition: an occasion on which a winner is selected from among two or more contestants

Other hypernyms of spelldown include contest.

spelldown (noun)	competition (noun)
a contest in which you are eliminated if you fail to spell a word correctly	the act of competing as for profit or a prize
	an occasion on which a winner is selected from among two or more contestants
	the contestant you hope to defeat
	a business relation in which two parties compete to gain customers