Peak \Peak\, v. i. [imp. & p. p. {Peaked}; p. pr. & vb. n. {Peaking}.] 1. To rise or extend into a peak or point; to form, or appear as, a peak. There peaketh up a mighty high mount. --Holand. 2. To acquire sharpness of figure or features; hence, to look thin or sicky. ``Dwindle, peak, and pine.'' --Shak. 3. [Cf. {Peek}.] To pry; to peep slyly. --Shak. {Peak arch} (Arch.), a pointed or Gothic arch.