marsh-mallow
noun
Definitions
A species of mallow, Althaea officinalis, that grows in marshy terrain.
A type of confectionery, originally (since Ancient Egyptian times) made from this plant, but now generally made of sugar or corn syrup, gelatin that has been pre-softened in water, gum arabic, flavorings, and sometimes beaten egg whites, all whipped to a spongy consistency.
Someone who is soft and benign.
Example: He acts like a total badass, but he's really just a marshmallow once you get to know him.