whipsaw

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A narrow two-person crosscut saw.
• transitive verb To cut with a whipsaw.
• transitive verb Games To win two bets from (a person) at one time, as in faro.
• transitive verb To cause to move or alternate rapidly in contrasting directions.
• transitive verb To defeat or best in two ways at once.

from The Century Dictionary.

• Hence, to beat, defeat, or cause to fail in two opposite ways at the same time. See the extract.
• noun A frame-saw with a narrow blade, used to cut curved kerfs. See cut under saw.
• To cut with a whip-saw.
• To have or take the advantage of (an adversary), whatever he does or may be able to do; particularly, in gamblers' slang, to win at faro, at one turn (two bets made by the same person, one of which is played open, the other being coppered); beat (a player) in two ways at once.

from the GNU version of the Collaborative International Dictionary of English.

• noun A saw for dividing timber lengthwise, usually set in a frame, and worked by two persons; also, a fret saw.
• noun A kind of narrow ripsaw, tapering from butt to point, with hook teeth and averaging from 5 to 71/2 feet in length, used by one or two men.
• transitive verb To saw with the whipsaw.
• transitive verb To defeat in, or cause to lose, two different bets at the same turn or in one play, as a player at faro who has made two bets at the same time, one that a card will lose and another that a different card will win; hence, to defeat in spite of every effort.
• transitive verb to cause to suffer a setback or losses by subjecting to two forces at the same time or in rapid succession.
• transitive verb (Finance) to cause to suffer a series of losses in trading when buying and selling at the wrong times in a rapidly fluctuating market; -- especially used when an attempt is made, by selling short, to recover losses from a long purchase in a declining market, and the short sale also results in a loss when the market subsequently rises. Used mostly in the passive.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a crosscut saw operated by two people
• verb to operate a whipsaw
• verb to lose potential profit by buying shares just before the price falls, or by selling them just before the price rises
• verb to defeat someone in two different ways at once

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a saw with handles at both ends; intended for use by two people
• verb saw with a whipsaw
• verb victimize, especially in gambling or negotiations