Correct Answer: dishonesty

Solution : The correct choice is the first option .

Explanation : Dishonesty is the opposite of decent, as it refers to a lack of honesty or integrity.

The meanings of the other options are as follows:

• Ethical refers to principles of right and wrong conduct, not directly opposite to "decent" but related.
• Downfall refers to a loss of power, status, or success, not an antonym of "decent".
• True refers to being in accordance with fact or reality, not an antonym of "decent".