What prefix could be added to this root word to form a word that matches the definition?

Answer:Prefixes are added to the beginning of a base word. It is not necessary to make any spelling changes to add a prefix to a base / root word.

Explanation:

Here are some prefixes with their varying meanings;

Bi - two / halves

Extra - beyond/outside

Fore - former/previous / front

Il - not

Im - not

Mis - incorrect/bad

Pre - before

Post - after

Re - again

Un - not

Examples of words with the above prefixes and different root words are; illegal, preheat, reread, extraordinary, postwar, misplaced, bimonthly, impossible, unkind, forehead.