forewarn

UK: /fɔː^rˈwɔː^rn/ US: /fɔrˈwɔrn/ ,(fôr wôrn′, fōr-)

WordReference Random House Learner's Dictionary of American English © 2026

fore•warn /fɔrˈwɔrn/   v. 

1. to warn in advance: [~ + object]
   Thunder forewarned us of the coming storm.
   [~ + object + of + object]
   We forewarned him of the danger.
   [~ + object + (that) clause]
   He was forewarned that his effort was useless.

WordReference Random House Unabridged Dictionary of American English © 2026

fore•warn  (fôr wôrn′, fōr-), v.t. 

1. to warn in advance.

• Middle English forwarnen. See fore-, warn 1300–50

fore•warn′er, n. 
fore•warn′ing•ly, adv. 
Synonyms

caution, admonish, alert, prewarn, tip off.

Collins Concise English Dictionary © HarperCollins Publishers::

forewarn / fɔːˈwɔːn/ verb (transitive)

1. to warn beforehand
2. forewarned is forearmed ⇒ if one knows about a problem or situation in advance, one will be able to deal with it when one needs to

foreˈwarner noun