The future is unfathomable; we must proceed carefully.
Tips
usage
Almost always appears in fixed phrases — most commonly 居心叵测 (jūxīnpǒcè, 'harboring sinister motives') and 前途叵测 ('an unpredictable future'). Rarely used as a free adjective.
memory
叵 is the character 可 (can) flipped horizontally — it literally means 'cannot.' So 叵测 = 'cannot measure / fathom.'