Select the most appropriate ANTONYM of the given word.
Confound

The correct option is Assure.

To find the most appropriate antonym of the given word, let us analyze its meaning and compare it with the options provided:

1. Confound: This verb means to cause surprise, confusion, or perplexity in someone, often by acting against their expectations, or to throw them into doubt.

Let us examine the definitions of the options:
- Expire: To run out of time, come to an end, or die. This is unrelated to confusion or certainty.
- Discern: To distinguish, perceive, or recognize something clearly.
- Assure: To make something certain, to guarantee, or to promise with confidence in order to dispel doubts or anxiety. Since to confound someone is to throw them into doubt or confusion, to assure them is to remove that doubt and build confidence, making it the direct antonym.
- Suppress: To forcibly put an end to or restrain something.

Hence, the most appropriate antonym of Confound is Assure.