Contemptible and contemptuous are close in meaning, but they are not interchangeable.
Contemptible describes someone or something that deserves contempt, scorn, or moral disapproval. It points to the target of the judgment. Example: His contemptible lies hurt the team. The lies are shameful, so they are contemptible.
Contemptuous describes a person, tone, look, or action that shows contempt. It points to the attitude being expressed. Example: She gave a contemptuous laugh and walked away. The laugh shows scorn, so it is contemptuous.
A simple way to remember the difference is this:
- Contemptible: deserving contempt.
- Contemptuous: feeling or showing contempt.
Compare these: The cheating was contemptible. His reply was contemptuous. In the first sentence, the behavior is morally bad. In the second, the reply expresses scorn.
If you mean worthy of scorn, choose contemptible. If you mean full of scorn, choose contemptuous.