anti / ante: prefixes
Anti- meaning against versus ante- meaning before.
Anti- means opposed to or preventing: antitrust, antiwar, antifreeze. Ante- means before in time or place: antebellum, antechamber, antedate. Hyphenate anti- before a capital letter or an identical vowel that would confuse the eye: anti-American, anti-inflation. Most closed forms stay closed: antiseptic, antitrust. Do not write anti- when you mean “earlier,” or ante- when you mean “against.”
Examples
Use Congress passed a new antitrust law.
Use The house is antebellum.
Avoid The house is anti-bellum.
Use an anti-inflammatory drug