- The definition of beware is to be cautious of and alert to potential dangers or risks.
If you need to be cautious of hitting a deer when driving on a dark road, this is an example of when you need tobeware of deer.
Beware of deer crossing this road.
beware definition by Webster's New World
beware definition by American Heritage Dictionary
verb be·wared, be·war·ing, be·wares verb, transitive
Origin: Middle English ben war : ben, to be; see be + war, on one's guard; see ware2.