indefinite quantity vs quantity

indefinite quantity and quantity both are nouns.

Word	Noun	Adjective	Verb	Adverb
indefinite quantity	Yes	No	No	No
quantity	Yes	No	No	No

As nouns, quantity is a hypernym of indefinite quantity; that is, quantity is a word with a broader meaning than indefinite quantity:

indefinite quantity: an estimated quantity
quantity: how much there is or how many there are of something that you can quantify

Other hypernyms of indefinite quantity include amount, measure.

indefinite quantity (noun)	quantity (noun)
an estimated quantity	how much there is or how many there are of something that you can quantify
	an adequate or large amount
	the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable