觀釁伺隙 [观衅－－]

Jyutping gun1 jan6 zi6 kwik1
Pinyin guān xìn sì xì

Definitions (CC-CEDICT)
  1. lit. to look for holes, and observe gaps (idiom)
  2. fig. to search out one's opponent's weak points
  3. to look for the Achilles' heel