Webster’s Revised Unabridged Dictionary · 1913
Flanker
Flank′er (·ẽr), n. One who, or that which, flanks, as a skirmisher or a body of troops sent out upon the flanks of an army toguard a line of march, or a fort projecting so as to command the side of an assailing body.
They threw out flankers, and endeavored to dislodge their assailants. W. Irwing.
Flank′er, v. t. [imp. & p. p. Flankered; p. pr. & vb. n. Flankering.] [See Flank, v. t.] 1. To defend by lateral fortifications. [Obs.] Sir T. Herbert.
2. To attack sideways. [Obs.] Evelyn.