Of an animal, esp. a lion: rearing or standing with the forepaws in the air, esp. in a threatening manner. Also figurative. Esp. in early use…

Of an animal, esp. a lion: standing erect, rearing, showing fierceness; (Heraldry) = rampant, adj. 1c. Also figurative and in figurative contexts.

That rises up (towards a vertical position or into the air); towering, standing high. Also figurative.