oddity vs crotchet

oddity and crotchet both are nouns.

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

As nouns, oddity and crotchet are synonyms defined as:

Other synonyms of oddity include queerness, quirk, quirkiness.

oddity (noun)	crotchet (noun)
something unusual -- perhaps worthy of collecting	a small tool or hooklike implement
a strange attitude or habit	a strange attitude or habit
eccentricity that is not easily explained	a musical note having the time value of a quarter of a whole note
	a sharp curve or crook; a shape resembling a hook