a tropical American mimosa plant, Mimosa pudica, the leaflets and stems of which fold if touched
2.
any similar plant, such as the leguminous plant Cassia nictitans of E North America
3. informal
a person who is easily upset
sensitive plant in American English
a tropical American plant (Mimosa pudica) of the mimosa family, with a spiny stem, minute, purplish flowers in spherical clusters, and leaflets that fold and leafstalks that droop at the slightest touch