Gibbous \Gib"bous\, a. [Cf. F. gibbeux. See {Gibbose}.] [1913 Webster] 1. Swelling by a regular curve or surface; protuberant; convex; as, the moon is gibbous between the half-moon and the full moon. [1913 Webster] The bones will rise, and make a gibbous member. --Wiseman. [1913 Webster] 2. Hunched; hump-backed. [Obs.] --Sir T. Browne. -- {Gib"bous*ly}, adv. -- {Gib"bous*ness}, n. [1913 Webster]