A person who exhibits an air of haughty confidence and independence but is, in reality, utterly inept, powerless, or insecure. Thought to be a reference to a pig stranded on a body of ice, freed from its pen but unable to walk or stand upright properly. The senator was as cool as a hog on ice before the press, flailing at a self-assured bravado despite the clear evidence tying him to the scandal. The movement, so cocksure in its demands for social reform, has become as independent as a hog on ice, as its leaders begin to feel the inevitable pressure of fickle voters.