Source : Webster's Revised Unabridged Dictionary (1913)

Bloodshot \Blood"shot`\, a. [Blood + shot, p. p. of shoot to
   variegate.]
   Red and inflamed; suffused with blood, or having the vessels
   turgid with blood, as when the conjunctiva is inflamed or
   irritated.

         His eyes were bloodshot, . . . and his hair disheveled.
                                                  --Dickens.

Source : WordNet®

bloodshot
     adj : (of an eye) reddened as a result of locally congested blood
           vessels; inflamed; "bloodshot eyes"