violent in action or spirit; raging; furious

a rampant leopard.

growing luxuriantly, as weeds.

in full sway; prevailing or unchecked

a rampant rumor.

(of an animal) standing on the hind legs; ramping.

Heraldry . (of a beast used as a charge) represented in profile facing the dexter side, with the body upraised and resting on the left hind leg, the tail and other legs elevated, the right foreleg highest, and the head in profile unless otherwise specified

a lion rampant.

Architecture . (of an arch or vault) springing at one side from one level of support and resting at the other on a higher level.

adjective

checked , controlled , limited , restrained

adjective

aggressive , blustering , boisterous , clamorous , dominant , epidemic , exceeding bounds , excessive , extravagant , exuberant , fanatical , flagrant , furious , growing , impetuous , impulsive , luxuriant , on the rampage , out of control , outrageous , pandemic , predominant , prevalent , profuse , raging , rampaging , rank , rife , riotous , spreading , tumultous/tumultuous , turbulent , unbridled , unchecked , uncontrollable , ungovernable , unrestrained , unruly , vehement , violent , wanton , widespread , wild , fierce , prevailing , threatening