fore·warn \fōrˈwȯ(ə)rn, fȯr-; fōəˈwȯ(ə)n, fȯ(ə)ˈ-\transitive verb Etymology: Middle English forwarnen, forewarnen, from for-, fore- fore- + warnen to warn — more at warn : to warn in advance: as a.: to give previous notice or information to < we were forewarned to expect you before dark > b.: to caution in advance especially in the form of an admonition < let me forewarn you, young man, you'll be sorry if you are late for supper > Synonyms:see warn