underhand
adj. 阴险的，秘密的，狡诈的；（球赛时投球）下投的；手心向上或向外的；（投球等）低手的（指手不过肩）
adv. 欺诈地；以下手投；（投球）低手地
例句
In softball, pitches are tossed underhand.
垒球运动中投球均是低手式投。
《柯林斯英汉双解大词典》
It is a sneaky and underhand way of doing business.
这是一种偷偷摸摸、见不得人的生意经。
I would never have expected her to behave in such an underhand way.
我从未想到她的行为竟如此阴险。
《牛津词典》
