-ive

mid-14c., "early; demanding haste, urgent; quick-tempered, angry;" late 14c. "speedy, swift, quick," by 1500s, from haste (n.) + -y (2); replacing or nativizing earlier hastif (c. 1300) "eager, impetuous," from Old French hastif "speedy, rapid; forward, advanced; rash, impetuous" (12c., Modern French hâtif), from haste (see haste (n.)). Meaning "requiring haste" is late 14c. (this is the sense in hasty-pudding, 1590s, so called because it was made quickly); that of "eager, rash" is from early 15c. Related: Hastiness. Old French also had a form hasti (for loss of terminal -f, compare joli/jolif, etc.), which may have influenced the form of the English word.

late 15c., "slow, moving with a slow pace or motion," from Old French tardif "slow, late" (12c.), also the name of the snail character in the Roman de Renart, from Vulgar Latin *tardivus, from Latin tardus "slow, sluggish; late; dull, stupid," a word of unknown origin; de Vaan gives it "no etymology."

The meaning "late, not acting or happening until after the proper or expected time" in English is from 1660s.

This word, not much used in English prose, is constantly employed in the U.S. and in Canada with reference to lateness in school-attendance. [Thornton, "American Glossary," 1912]

Related: Tardily; tardiness. Earlier forms of the word in English were tardif, tardyve (late 15c.). Modern tardive "characterized by laxness; tending to be late," 1905, is said to be a new borrowing from French. Seventeenth-century English lexicons (Blount. Coles, Cockeram) have tardiloquent "speaking slowly, drawling."