adj.1 (placed after noun) Heraldry (of an animal) standing on its left hind foot with its forepaws in the air (lion rampant).
2 unchecked, flourishing excessively (rampant violence).
3 violent or extravagant in action or opinion (rampant theorists).
4 rank, luxuriant.
Derivatives:
rampancy n. rampantly adv.
Etymology: ME f. OF, part. of ramper: see RAMP(1)