ploy
n.
1722, "anything with which one amuses oneself," Scottish and northern England dialect, possibly a shortened form of employ or deploy. Popularized in the sense "move or gambit made to gain advantage" by British humorist Stephen Potter (1900-1969).
词根：ploy = use, invlve, 表示“用, 参与”
employ v. 雇佣；运用（em进入+ploy→进入用的状态→雇佣）
employment n. 雇佣，就业（employ+ment）
deploy v. 调度；部署（部队）（de加强+ploy→加强使用[部队]→调度）
ploy n. （取胜的）策略，手法