underhand       
 adjective mainly UK disapproving uk/ˌʌn.dəˈhænd/ us/ˌʌn.dɚˈhænd/ (US usually underhanded)
 秘密的,偷偷摸摸的
done secretly, and sometimes dishonestly, in order to achieve an advantage
  What really angered her was the dirty, underhand way they had tricked her. 真正使她愤怒的是他们竟用卑鄙手段欺骗她。 
 underhand       
adjective, adverb US uk/ˌʌn.dəˈhænd/ us/ˌʌn.dɚˈhænd/ (UK underarm)
 下手的(地),低手的(地)
(done by) moving the arm below shoulder level
  underhand throwing 低手投球 
 He pitched underhand for the younger children. 他给年纪小些的孩子投低手球。 
 Opposite: overhand