Infinity (n.) in its true transcendental sense is not a very large quantity but a synthesis that can never be completed.
Infinity (n.) is not a maximum but a relation to an arbitrary unit: make the unit bigger or smaller and the infinite stays just as infinite.
Infinity (n.) in progress says 'you ought never to stop', while indefinite progress says 'extend it as far as you want' — for a line one can draw, the difference is an empty subtlety.
Infinity (n.) of a line drawn in indefinitum presupposes a space and time that can only inhere in intuition — it could never be concluded from concepts.
Infinity (n.) in the Kantian notion is only an ideal of reason — the finite projected and amplified; the infinite presupposes the finite, the most anti-Cartesian point of that philosophy.