The prefix that makes a root word or base word negative is "dis-".
The prefix that makes a root word or base word negative is "dis-". To determine this, you can use a dictionary or a word analysis reference. In this case, you can notice that the word "dis-" represents negation or the opposite of something. For instance, "discontinue" means to stop or terminate, "disagree" means to have a different opinion, and "disapprove" means to not approve.
