In each of the following questions, choose the word that is most nearly opposite in meaning to the word given in capitals. Here, the word is WANE, which is used to describe something that is decreasing or becoming weaker.

Introduction / Context:
This question focuses on antonyms, that is, words with opposite meanings. The word WANE commonly appears in phrases such as public interest began to wane or the moon is on the wane, meaning that interest or size is decreasing. To answer correctly, you must recognise this sense of decline and then select the option that conveys growth or increase, providing a natural opposite.

Given Data / Assumptions:
- Target word: WANE. - Options: Widen, Poor, Swell, Tight. - One option should clearly express the idea of increase to oppose the idea of decrease.

Concept / Approach:
Wane means to decrease in power, intensity, or size. The classic example is the waning moon, which appears to shrink. The opposite concept is to grow, expand, or become larger. Swell is widely used in English to mean to grow in size or volume, and can also refer to rising waves or swelling crowds. While widen involves becoming broader in one dimension, swell captures the general idea of expansion in a more complete and idiomatic way. The other options do not reflect the reverse of waning.

Step-by-Step Solution:
Step 1: Remember that wane refers to diminishing strength, brightness, size, or intensity. Step 2: Consider option A, Widen, which focuses on an increase in width only. While it indicates some form of growth, it is not the standard opposite of wane. Step 3: Consider option B, Poor, which refers to lack of money or quality. It is unrelated to increase or decrease in intensity over time. Step 4: Consider option C, Swell, which means to grow, expand, or become larger, and is commonly used as the reverse of shrinking or waning. Step 5: Consider option D, Tight, which describes how firmly something is fixed or how snugly it fits. It does not relate to the idea of waning.

Verification / Alternative check:
Check by substituting the words into a similar sentence. If we say enthusiasm began to wane, the opposite sentence would be enthusiasm began to swell, meaning enthusiasm started to grow. Saying enthusiasm began to widen sounds odd, and the other options do not make sense. Similarly, when the moon wanes, it appears smaller; when something swells, it appears bigger. This substitution test confirms that swell most accurately expresses the opposite of wane among the choices.

Why Other Options Are Wrong:
Widen is wrong because it is limited to width and is not the usual direct antonym in this context. Poor is wrong because it talks about wealth or quality, not changes in intensity or size over time. Tight is wrong because it describes fit or tension rather than temporal decrease or increase.

Common Pitfalls:
A common error is to pick words that appear vaguely related to size or quality without checking whether they are actually used as opposites in real expressions. Another pitfall is ignoring typical collocations like on the wane and on the swell or swell of the crowd. Building an awareness of common phrases through regular reading helps you avoid such mistakes and recognise antonyms more confidently.

Final Answer:
The word most nearly opposite in meaning to WANE is Swell.