Monstrosity
mid 16th century (denoting an abnormality of growth): from late Latin monstrositas, from Latin monstrosus (see monstrous).
wiktionary
From Middle English monstruosite, from Late Latin monstrositas(“monstrousness”), from Latin monstrōsus.
etymonline
monstrosity (n.)
1550s, "an abnormality of growth," from Late Latin monstrositas "strangeness," from Latin monstrosus, a collateral form of monstruosus (source of French monstruosité), from monstrum "divine omen, portent, sign; abnormal shape; monster, monstrosity," figuratively "repulsive character, object of dread, awful deed, abomination," from root of monere "to admonish, warn, advise," from PIE *moneie-"to make think of, remind," suffixed (causative) form of root *men- (1) "to think."
Earlier form was monstruosity (c. 1400). Sense of "state or quality of being monstrous" is first recorded 1650s. Meaning "a monster" is attested from 1640s.
