顺手牵羊

順手牽羊
shùnshǒuqiānyáng
  1. lit. to lead away a goat while passing by (idiom)
  2. fig. to opportunistically pocket sb's possessions and walk off

CEDICT

  1. (figurative) to steal something under the cover of an emergency; to take advantage of a crisis for personal gain
  2. to steal something under the cover of an emergency; to take advantage of a crisis for personal gain

Wiktionary

趁便顺势，取走他人的财物。《黄绣球．第三回》：「这一天见来的很是不少，黄通理更代为踌躇，怕的是越来越多，容不下去，而且难免有趁火打劫，顺手牵羊的事。」比喻趁机行事，容易而不费力。元．尚仲贤《单鞭夺槊．第二折》：「是我把右手带住马，左手揪着他眼扎毛，顺手牵羊一般牵他回来了。」

重編國語辭典

  1. 方便行事，毫不费力
  2. 趁便顺势，取走他人的财物

維基詞典

Entry Composition

1 顺手 shùnshǒu
  1. as an incidental action while doing sth else; while one is at it; in passing
  2. smooth; easy; without difficulty
2 牵 qiān
  1. to lead along
  2. to pull (an animal on a tether)
  3. (bound form) to involve
  4. to draw in
3 羊 yáng sheep; goat

classifiers: 頭, 隻