idiosyncrasy vs speciality

idiosyncrasy and speciality both are nouns.

Word	Noun	Adjective	Verb	Adverb
idiosyncrasy	Yes	No	No	No
speciality	Yes	No	No	No

As nouns, speciality is a hypernym of idiosyncrasy; that is, speciality is a word with a broader meaning than idiosyncrasy:

idiosyncrasy: a behavioral attribute that is distinctive and peculiar to an individual
speciality: a distinguishing trait

Other hypernyms of idiosyncrasy include distinctiveness, peculiarity, specialness, specialty.

idiosyncrasy (noun)	speciality (noun)
a behavioral attribute that is distinctive and peculiar to an individual	the special line of work you have adopted as your career
	a distinguishing trait
	an asset of special worth or utility