the part of one's field of vision, as to the side and rear, where one is unable to see approaching objects.
the side opposite that toward which a person is looking.
Origin of blind side
First recorded in 1600–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
rugby the side of the field between the scrum and the nearer touchline
the side on which a person's vision is obscured
(tr) US to take (someone) by surprise
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
"unguarded aspect," c.1600; see blind (adj.). As a verb, also blind-side, blindside, "to hit from the blind side," first attested 1968, American English, in reference to U.S. football tackles.
Online Etymology Dictionary, © 2010 Douglas Harper
see under blind spot.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.