winterkill verb 2noun 1forms 3 verb2 •To kill by the conditions of winter, especially the effect of the cold, freezing.From these data it is evident that the frequent low temperatures may have winterkilled many bare fields of common alfalfa before the ice sheets occurred the latter part of February 1922 — 1919 •To die from the above effects of winter conditions.Order new rose bushes to replace any that have winterkilled. — 1951 noun1 •The mortality resulting from lethal wintry conditions among a human, animal, and/or vegetal population. formswinterkilled · winterkilling · winterkills