‘猜忌’ is a compound verb meaning ‘to suspect’ or ‘to be distrustful’, especially toward someone close—like a friend, colleague, or partner—without solid evidence. The first character 猜 (cāi) means ‘to guess’ or ‘to suspect’, implying uncertainty and speculation; the second character 忌 (jì) means ‘to fear’, ‘to resent’, or ‘to avoid’, often carrying emotional weight like jealousy or apprehension. Together, they describe a negative emotional state rooted in insecurity, where doubt hardens into mistrust.

This word is commonly used in interpersonal contexts—such as relationships, teamwork, or family dynamics—to express unwarranted suspicion that damages trust. It carries a distinctly negative connotation and often implies irrationality or emotional fragility. Unlike neutral words like 怀疑 (to doubt), 猜忌 suggests an emotional, even paranoid, attitude, sometimes linked to envy or possessiveness. It frequently appears in literature, psychological discussions, and advice about healthy communication.