An example of foreshadow is to introduce a weapon into a movie scene, which will later be used in combat.
Origin of foreshadowfore- + shadow (transitive verb): that is, to be the shadow thrown ahead of (something)
transitive verbfore·shad·owed, fore·shad·ow·ing, fore·shad·ows
(third-person singular simple present foreshadows, present participle foreshadowing, simple past and past participle foreshadowed)
From fore- + shadow.