Correct Answer: Dullness

Solution : The correct choice is the fourth option.

Glamour refers to charm, attractiveness, or fascination.
Dullness , as the antonym, signifies a lack of charm or excitement, something plain or uninteresting.

The meanings of the other options are as follows:

• Charm represents a quality of attractiveness or delight.
• Magnanimous refers to generosity or a noble spirit.
• An appeal indicates attraction or desirability.

Therefore, the correct answer is dullness.