E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Heavy Man (The),
in theatrical parlance, means an actor who plays foil to the hero, such as the king in Hamlet, the mere foil to the prince; Iago is another heavy mans part as foil to Othello; the tiger in the Ticket of Leave Man is another part for the heavy man. Such parts preserve a degree of importance, but never rise into passion.