Without sight

sightless, unseeing, eyeless, blinded, visionless, in darkness, dim-sighted, visually impaired, groping (in the dark), deprived of sight, sun-blind, purblind, undiscerning, stone-blind, moon-blind, blind as a bat*.

Antonyms observant*, seeing*, sighted*, keen-sighted. *

Without thought or reason

heedless, irrational, impetuous, unthinking; see careless 1, rash.

Without perceiving or understanding

obtuse, unseeing, unaware, oblivious, unconscious, imperceptive, undiscerning, by guesswork, by calculation, with instruments; see also unaware.

Antonyms observant*, perceptive*, discerning. *

Without passage

obstructed, blocked, without egress; see tight 2.

Concealed

secluded, obscured, out of sight; see hidden 2.

Random

chance, accidental, unplanned; see accidental 1.

An obstruction to light or sight

blindfold, blinder, blinker, shade, Venetian blind, window shade, mini-blind, vertical blind, shutter, screen; see also curtain, veil 2.

Something intended to deceive

front, cover, trap, decoy; see camouflage 1, trick 1.

To obscure

darken, shadow, dim, blindfold; see shade 1, 2.

To deceive

conceal, delude, mislead, dazzle; see deceive.