(adjective)
(in heraldry) an animal represented standing on one hind foot with its forefeet in the air, typically in profile, facing the left side, with right hind foot and tail raised (unless otherwise specified) (see the flags of Wales);
e.g. One sees lions rampant depicted on several of the ancient Welsh heraldic banners.
(adjective)
architectural term for 'tilted': said of an arch with one side higher than another, or a vault whose two abutments are on an inclined plane;
e.g. The image of a rampant arch does not conjure up easily, but when you can find one, the picture is quite striking.