Verified answer

Are you in Safari or Firefox? In Safari, this feature is called Autofill, and you can turn it off in the Safari Preferences. Look for the big "AutoFill" button at the top of the preferences panel.

In Firefox, go to Preferences and then choose "Privacy." Look for the checkbox where it asks, "Remember what I enter in forms and the search bar." Uncheck that.

If you're talking about the Mac's "Spotlight" software - the internal search program, I don't believe you can turn it off there.

If you're in the Mail program, go to Preferences and choose the "Composing" tab -- uncheck the box that says "Automatically complete addresses."

If you're talking about a different program, look for things like the above in the Preferences panel.

Hope this helps!

Well, if you're using Safari you go to Safari > Preferences > Autofill > and then uncheck the check boxes...or gives you some vague idea of how to do it.

Hope that helps.