戒备 (jiè bèi) literally combines 戒 (jiè), meaning 'to guard against' or 'to warn', and 备 (bèi), meaning 'to prepare' or 'to be ready'. Together, they form a verb meaning 'to be on guard' or 'to stand ready for possible danger'. It implies alertness, vigilance, and mental or physical preparation in anticipation of threat or uncertainty.

This word is commonly used in contexts involving security, defense, wildlife behavior, or tense social situations. For example, animals often display戒备 when sensing predators — freezing, raising fur, or staring intently. Humans use it when entering unfamiliar places, during emergencies, or in negotiations where trust is low. Though it can describe a state (e.g., 'in a state of alert'), 戒备 itself functions as a verb and is rarely used as a noun without modification (e.g., 戒备状态). It carries a slightly formal or serious tone, more common in written Chinese and news reports than casual speech.