oddity vs odd

oddity is a noun but odd is not a noun.

Word	Noun	Adjective	Verb	Adverb
oddity	Yes	No	No	No
odd	No	Yes	No	No

oddity (noun)	odd (noun)
something unusual -- perhaps worthy of collecting
a strange attitude or habit
eccentricity that is not easily explained

oddity (adjective)	odd (adjective)
	not divisible by two
	an indefinite quantity more than that specified
	of the remaining member of a pair
	beyond or deviating from the usual or expected
	not used up
	not easily explained