1. the part of one's field of vision, as to the side and rear, where one is unable to see approaching objects.
2. the side opposite that toward which a person is looking.
Pronunciation: (blīnd'sīd"), [key]
—v.t., -sid•ed, -sid•ing.
1. Sports.to tackle, hit, or attack (an opponent) from the blind side: The quarterback was blindsided and had the ball knocked out of his hand.
2. Informal.to attack critically where a person is vulnerable, uninformed, etc.: The president was blindsided by the press on the latest tax bill.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.