improper fraction vs fraction

improper fraction and fraction both are nouns.

Word	Noun	Adjective	Verb	Adverb
improper fraction	Yes	No	No	No
fraction	Yes	No	Yes	No

As nouns, fraction is a hypernym of improper fraction; that is, fraction is a word with a broader meaning than improper fraction:

improper fraction: a fraction whose numerator is larger than the denominator
fraction: the quotient of two rational numbers

improper fraction (noun)	fraction (noun)
a fraction whose numerator is larger than the denominator	a small part or item forming a piece of a whole
	the quotient of two rational numbers
	a component of a mixture that has been separated by a fractional process

improper fraction (verb)	fraction (verb)
	perform a division