The adjective was formed by suffixation: īnfīnītus (“boundless”, “unlimited”, “infinite”: “endless”; “countless”; grammar “indefinite”, "infinitive”) + -īvus (“suffix forming adjectives”); the noun is an elliptical use for modus īnfīnītīvus (“[the] infinitive mood”). The Latin is a rough translation of the Greek ἀπαρέμφατος, meaning "not indicated" or "not determined."