One prefix unlocks many words. What does 'anti-' mean in antibiotic, antisocial, and antifreeze?

The prefix "anti-" means "against" or "opposite," which explains why an antibiotic works against bacteria, an antisocial person avoids or opposes social interaction, and antifreeze prevents (works against) liquids from freezing. Recognizing a single prefix's meaning unlocks understanding of dozens of related words at once.

"Together" and "before" are meanings of entirely different prefixes — "together" resembles "co-" or "syn-," while "before" is the meaning of "ante-," a prefix that looks and sounds almost identical to "anti-" but comes from a different root and carries a different meaning.

The near-identical spelling of "anti-" and "ante-" causes genuine confusion even among native speakers — words like "antebellum" (before the war) and "antipathy" (against/opposed feeling) look deceptively similar despite having opposite underlying logic.