1 Move (troops or equipment) into position for military action.
1.1 no object (of troops) move into position for military action.
2 Bring into effective action.
Late 18th century from French déployer, from Latin displicare and late Latin deplicare ‘unfold or explain’, from dis-, de- ‘un-’ + plicare ‘to fold’. Compare with display.
High command deployed mock planes and troop emplacements as a ploy to make the enemy move their real forces into the wrong place.