I. noun
: a common pimpernel ( Anagallis arvensis ) having scarlet, white, or purplish flowers that close at the approach of rainy or cloudy weather — called also poor man's weatherglass, red pimpernel
II. noun
Etymology: after The Scarlet Pimpernel, assumed name of hero of The Scarlet Pimpernel (1905), romance by Baroness Emmuska Orczy died 1947 English novelist and playwright
: a person who rescues others from mortal danger by smuggling them across a border