shrewd 
/ˈʃru:d/ adjective
shrewd·er; shrewd·est /ˈʃru:d/ adjective [also more shrewd; most shrewd] : having or showing an ability to understand things and to make good judgments : mentally sharp or clever
▪ a shrewd observer/businessman ▪ She's shrewd about her investments. ▪ a shrewd observation
▪ a shrewd observer/businessman ▪ She's shrewd about her investments. ▪ a shrewd observation
— shrewd·ly adverb
— shrewd·ness noun [noncount]
