Answer: canniest

AnswerCrossword Clue
CANNIESTMost sharp-witted
CANNIESTMost astute
CANNIESTMost prudent
CANNIESTMost careful and shrewd
CANNIESTMost shrewd
CANNIESTMost ingenious
canniestshrewd
canniestCANNIE, prudent, also CANNY
canniestcareful