Select the most appropriate ANTONYM of the given word.
Modest

The correct answer is Conceited.

Step-by-step Explanation:

1. Analyze the given word:
The word Modest refers to someone who is humble, unassuming, or moderate in the estimation of their own abilities, achievements, or value. They do not boast or brag about themselves.

2. Define the antonym:
An antonym is a word that has the opposite meaning. Therefore, the antonym of "modest" must describe someone who has an excessively high opinion of themselves, boasts about their achievements, or is excessively proud.

3. Evaluate the given options:
• Glum: Means looking or feeling dejected, morose, or gloomy. This is unrelated to modesty.
• Sullen: Means bad-tempered, gloomy, or sulky. This is unrelated to modesty.
• Unhappy: Means sad, miserable, or dissatisfied. This is unrelated to modesty.
• Conceited: Means excessively proud of oneself, vain, or arrogant. This is the direct opposite of being humble or modest.

4. Conclusion:
Since "conceited" represents having an inflated self-image and pride, it is the most appropriate antonym for "modest".