1. As a verb meaning "to direct one's eyes towards something":
* Ignore: to pay no attention to something.
* Avoid: to deliberately keep away from something.
* Overlook: to fail to notice something.
2. As a verb meaning "to appear":
* Disappear: to vanish from sight.
* Conceal: to hide something from view.
3. As a noun meaning "an appearance":
* Disguise: something that hides one's true appearance.
* Invisibility: the state of being unseen.
To give you a more precise opposite, please provide the sentence or context in which you are using "look".