What does the prefix "anti-" mean?

The prefix "anti-" means "against." This prefix is commonly used in various contexts to indicate opposition or counteraction to something. For example, in words like "antibiotic," which refers to a substance that destroys or inhibits the growth of bacteria, the "anti-" component signifies a stance that is opposed to bacteria. Understanding this prefix can enhance your vocabulary and comprehension of numerous English words, especially in scientific and medical terminology.

The other options represent different meanings but do not apply in this case. For instance, "pro" means favoring or supporting something, "before" generally refers to time or order, and "with" implies being in the company of or in addition to. All these meanings diverge from the clear opposition indicated by "anti-."