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1. Catch unawares, especially with harmful consequences
   "The economic downturn blindsided many investors"
    
2. Attack or hit on or from the side where the attacked person's view is obstructed

1. The side on which your vision is limited or obstructed

Derived forms: blindsiding, blind sides, blindsides, blindsided

Type of: assail, assault, attack, set on, side, surprise

Encyclopedia: Blindside