Flanker
Flanker , noun
One who, or that which, flanks, as a skirmisher or a body of troops sent out upon the flanks of an army to guard 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.
Flanker , transitive verb
[See Flank, transitive verb]
1.
To defend by lateral fortifications. [Obsolete] — Sir T. Herbert
2.
To attack sideways. [Obsolete] — Evelyn