Beware comes from Middle English be war ('be wary'), from be (imperative of be) + war/ware ('cautious'), from Old English wær ('aware, cautious'). The historical trail runs through wær in Old English and *waraz in Proto-Germanic. Morphologically, beware is transparent: it draws on Middle English be war ('be wary'), from be (imperative of be) + war/ware ('cautious'), from Old English wær ('aware, cautious'). Used as a verb, beware now means "be cautious or on guard against a danger", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in related forms such as wary, aware, and ware. The modern word remains analyzable through its parts, which makes the semantic connection unusually direct.