1. Having keen eyesight; quick to notice visual details
   "The sharp-sighted ranger spotted the bird a mile away";
   - Argus-eyed, hawk-eyed, keen-sighted, lynx-eyed, quick-sighted, sharp-eyed, eagle-eyed
    
2. Keenly observant, perceptive or alert, especially in noticing flaws or deception
   "The sharp-sighted auditor caught the accounting error";
   - quick-sighted, sharp-eyed, keen-eyed, eagle-eyed

See also: perceptive, sighted