In this English vocabulary question, you must choose the word that is opposite in meaning (antonym) to "Tremulous", a word that usually describes something shaking, quivering, or showing nervousness and lack of confidence.

Introduction / Context:
This question checks your understanding of antonyms in English vocabulary. The word "Tremulous" is often used to describe a voice, hand, or manner that is shaky or quivering because of fear, weakness, or nervousness. To find the correct antonym, you need a word that expresses the idea of steadiness or firmness instead of shaking or uncertainty.

Given Data / Assumptions:
- The target word is "Tremulous".
- The options are "Feeble", "Frugal", "Stable", and "Vital".
- Standard dictionary meanings are assumed.
- Only one option should clearly present an opposite sense to "Tremulous".

Concept / Approach:
"Tremulous" suggests shaking, quivering, or easily affected by fear. The antonym therefore should express steadiness, firmness, or lack of movement. When solving antonym questions, restate the target word in a simpler phrase. For example, "tremulous" can be restated as "unsteady and shaking". You then look for an option that conveys "steady and firm", which directly opposes the original meaning.

Step-by-Step Solution:
Step 1: Interpret "Tremulous" as quivering, shaking, or timid. Step 2: Consider "Feeble". This means weak or lacking physical strength, which can be related to tremulous, not opposite. Step 3: Consider "Frugal". This describes someone who is economical in the use of resources and has no direct link to shaking or steadiness. Step 4: Consider "Stable". This means firm, steady, and not likely to move or change suddenly, which is the opposite of tremulous. Step 5: Consider "Vital". This relates to energy and life, but does not address the idea of shaking versus steadiness directly.

Verification / Alternative check:
If a tremulous hand is unsteady and shaking, a stable hand would be firm and not trembling. The conceptual contrast is very clear: tremulous equals shaky, stable equals steady. "Feeble" can actually coexist with tremulous, since a feeble person may have tremulous movements. "Frugal" and "Vital" refer to completely different concepts. Therefore, "Stable" is the best antonym and fits the logic of contrasting movement and steadiness.

Why Other Options Are Wrong:
"Feeble" is wrong because it refers to weakness, which may even cause tremulous behaviour, so it is associated rather than opposite. "Frugal" is wrong because it deals with careful spending or use of resources. "Vital" is wrong because it signifies energetic and full of life. None of these convey the firm steadiness that truly counterbalances the sense of tremulous.

Common Pitfalls:
A common error is to pick a word just because it sounds sophisticated or unrelated, instead of a true antonym. Another mistake is to treat words like "Feeble" as opposites simply because exam takers loosely connect them with weakness, whereas both tremulous and feeble can occur together. Always ask yourself whether the chosen option really reverses the idea presented by the original word.

Final Answer:
The word that is opposite in meaning to "Tremulous" is Stable.