aggression: [17] The violent associations of aggression have developed from the much milder notion of ‘approaching’ somebody. The Latin verb aggredī ‘attack’ was based on the prefix ad- ‘towards’ and gradī ‘walk’, a verb derived in its turn from the noun gradus ‘step’ (from which English gets, among many others, grade, gradual, and degree). => degree, grade, gradual[aggression etymology, aggression origin, 英语词源]