Entry 1 sense Webster, 1913 blindside /blīn'-dsīdˌ/ · IPA /ˈblaɪndˌsaɪd/ 01 v. t. to attack a person from his blind side; metaphorically, to give a person an unpleasant suprise. 1. to attack a person from his blind side; metaphorically, to give a person an unpleasant suprise.