cagey, cagy, canny, clever -- (showing self-interest and shrewdness in dealing with others; "a cagey lawyer"; "too clever to be sound")
apt, clever -- (mentally quick and resourceful; "an apt pupil"; "you are a clever man...you reason well and your wit is bold"-Bram Stoker)
clever, cunning, ingenious -- (showing inventiveness and skill; "a clever gadget"; "the cunning maneuvers leading to his success"; "an ingenious solution to the problem")
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