Step 1: Understanding the Concept:
To find the antonym (opposite) of a word, we must first understand its literal and figurative meanings.
``BILIOUS'' comes from the root ``bile.'' In old medicine, an excess of yellow bile was thought to make a person irritable, cranky, and bad-tempered.
In modern English, it also describes a sickly yellow color or the feeling of nausea, but in a behavioral context, it means someone who is unpleasant and grumpy.
Step 2: Detailed Explanation:
Let's analyze the options:
1. BILIOUS (Target): Bad-tempered; irritable; unpleasant.
2. Amiable (Option A): Having or displaying a friendly and pleasant manner. This is the direct opposite of being grumpy or irritable.
3. Peevish (Option B): Easily irritated, especially by unimportant things. This is a synonym for bilious.
4. Valiant (Option C): Possessing or showing courage or determination; brave. This is unrelated to mood or temperament.
5. Sallow (Option D): (Of a person's face) of an unhealthy yellow or pale brown color. While this describes the {appearance} of a bilious person, it is not an antonym.
By comparing the temperaments, an ``amiable'' person is someone people enjoy being around, while a ``bilious'' person is someone people avoid. This makes them perfect opposites.
Step 3: Final Answer:
The word most nearly opposite to BILIOUS is Amiable (Option A).