What does "forced" mean?

Forced: Done or produced with force or great labor, or by extraordinary exertion; hurried; strained; produced by unnatural effort or pressure; as, a forced style; a forced laugh. Forced draught. See under Draught. -- Forced march (Mil.), a march of one or more days made with all possible speed. -- For"ced*ly, adv. -- For"ced*ness, n.