blind as a bat/beetle/mole

(as) blind as a bat

1. Unable to see at all. After neglecting his vision for years, my grandfather became blind as a bat, unable to even see shadows.

2. Having poor vision. I've worn glasses for 20 years, so I'm as blind as a bat now.

3. Oblivious to something. Are you blind as a bat? Those two have been flirting all afternoon!

(as) blind as a beetle

dated

1. Unable to see well or at all. My grandfather was born blind as a beetle, so he's never known what anything truly looks like. I've worn glasses for 20 years—I'm as blind as a beetle without them!

2. Totally oblivious to something. Are you blind as a beetle? Those two have been flirting all afternoon! You must be as blind as a beetle if you don't see the problem with this plan.

(as) blind as a mole

dated

1. Unable to see well or at all. My grandfather was born blind as a mole, so he's never known what anything truly looks like. I've worn glasses for 20 years—I'm as blind as a mole without them!

2. Totally oblivious to something. Are you blind as a mole? Those two have been flirting all afternoon! You must be as blind as a mole if you don't see the problem with this plan.

blind as a bat/beetle/mole

Totally blind, or, figuratively, unseeing. None of these animals is, by the way, truly blind. The bat flies about in the dark in seemingly erratic paths (see bats in one’s belfry), and the beetle and mole burrow through the ground. Nevertheless, these similes are quite old and have become clichés. The bat analogy dates from the sixteenth century at least (John Harvey); the mole and beetle similes come from Roman times and were cited in translations by Erasmus.