| A | B |
| anti | against |
| antiaircraft | used in defense against enemy aircraft |
| antibiotic | substance that destroys or weakens harmful micoorganisms. Penicillin is one of these types of medicine. |
| antidote | medicine or remedy that counteracts the effects of a poison |
| antifreeze | liquid with a low freezing point added to the cooling point in the radiator of an internal combustion engine to prevent the cooling system from freezing |
| antiseptic | substance that prevents the growth of germs that cause infection |
| antisocial | opposed to the principles upon which society is based |
| anticipate | look forward to; expect |
| antique | old-fashioned |
| antigravity | any force that opposed gravity |
| antitoxin | antibody formed in response to the presence of a toxin to prevent or reduce the effects of that toxin |
| toxin | poison |
| septic | causing infection |