Fill in the blank with most appropriate word.

I am ______ of joining the armed forces.

desirous

The most appropriate word to fill in the blank is desirous.

The words interested, keen, and eager all mean to have a strong interest in something. However, desirous has a more specific meaning of wanting something very much. This is the most accurate word to describe the feeling of wanting to join the armed forces.

The word interested is too general, and it does not convey the same sense of urgency or commitment as desirous. The word keen is also too general, and it can be used to describe a wide range of feelings, from mild interest to intense excitement. The word eager is more specific than keen, but it still does not convey the same sense of seriousness as desirous.