What does forewarn mean?
To forewarn is to warn someone in advance — to give notice of a danger, obstacle, or unpleasant development before it arrives, so that they can prepare for it or avoid it altogether. The word is typically used with 'of' or 'about' (forewarned of the delays, forewarned about the storm) and appears most naturally in formal or semi-formal contexts: news reports, official notices, business communications, and cautionary advice. Its enduring cultural weight owes much to the proverb 'forewarned is forearmed,' which expresses the idea that advance knowledge itself is a form of protection. Forewarn carries a serious, prudent connotation rather than an alarmist one; it implies care and responsibility on the part of the warner rather than panic. Though somewhat old-fashioned compared with plainer terms like alert or notify, it remains a precise and respected way of signalling that a warning has come early enough for action to be taken.
verbTo warn someone in advance of something, especially danger, difficulty, or an unwelcome event.
- To warn someone beforehand about a danger, problem, or undesirable event; often used with 'of' or 'against'.
"Meteorologists forewarned residents along the coast well before the hurricane made landfall."
"The bank had been forewarned of the attempted fraud and acted swiftly to protect customer accounts."
"Let me forewarn you: the final exam is far harder than the practice tests suggest."
"Forewarned is forearmed" — this proverb has kept forewarn in everyday English for over four centuries, pairing two Old English roots into a single word of caution.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of forewarn
Forewarn derives from the Old English verb 'warnian' (to warn), combined with the prefix 'fore-', meaning 'beforehand'. Both elements are native Germanic roots rather than borrowings from Latin or Greek. The compound emerged in Middle English, with the phrase 'forewarned, forearmed' attested by at least the sixteenth century. Cognates sharing the same root include 'wary', 'beware', and 'warning' itself.
Related word forms
How forewarn is actually used
Formal to neutral register. Typically followed by 'of' (the danger ahead) or occasionally 'against' (a person or course of action). Frequently appears in the passive form ('we were forewarned'). The related proverb 'forewarned is forearmed' — meaning prior knowledge enables preparation — is far more widely quoted than any other use of the word.
Easily confused with forewarn
Foreshadow means to hint at or suggest a future event indirectly, while forewarn means to explicitly and directly warn someone in advance.