In the following question, choose the word which is opposite in meaning to the given word INFIRM. The word infirm is often used to describe someone who is physically weak, feeble, or lacking in strength, especially due to age or illness. Select the option that best expresses the opposite sense of strength and firmness.

Introduction / Context:
This vocabulary question tests the concept of antonyms in English. The word given is INFIRM, which commonly appears in descriptions of people who are physically weak, frail, or lacking bodily strength, often due to age or long illness. To answer correctly, the learner must recall or infer the meaning of the word and then select the option that is opposite in sense, not merely unrelated. Such questions are frequent in competitive examinations, where a clear understanding of word meanings, usage, and nuances helps to build strong language skills and improves reading comprehension as well as written expression.

Given Data / Assumptions:

• Word given: INFIRM.
• Task: choose the word that is opposite in meaning to INFIRM.
• Options: Strong, Weak, Supporter, Believer.
• Assumption: infirm is used in its common meaning related to physical weakness or frailty.

Concept / Approach:
An antonym is a word that has the opposite meaning to another word. The word infirm is usually used to describe someone who is not physically robust, who is weak or feeble in body or health. Therefore, we must look for an option that describes the quality of being physically robust, firm, or powerful in contrast to that weakness. It is important to distinguish between words related to strength or weakness and words that describe totally different ideas, such as beliefs or roles. This ensures that the chosen option directly contrasts with the given word rather than merely being unrelated vocabulary.

Step-by-Step Solution:
Step 1: Recall or deduce the meaning of INFIRM. It means weak, feeble, or lacking physical strength. Step 2: Identify the sense we need for the antonym: the opposite of weak, that is strong or firm. Step 3: Examine the options: Strong refers to having great physical power or firmness, which is a direct opposite. Step 4: Weak is actually similar in meaning to infirm, so it is a synonym, not an antonym. Step 5: Supporter and Believer refer to roles or attitudes and do not relate to physical strength, so they are not opposites. Step 6: Conclude that Strong is the only word that meaningfully expresses the opposite of infirm.

Verification / Alternative check:
A simple way to verify the answer is to form example sentences. Consider the phrase infirm old man, which clearly describes someone who is physically weak. The opposite kind of description would be strong young athlete or strong healthy man. If we replaced infirm with strong in a sentence, the meaning would reverse. On the other hand, replacing infirm with weak would not change the sense of the sentence, which confirms that weak is similar rather than opposite. Supporter and believer would not fit naturally in the same descriptive structure because they refer to a person's role or mental attitude, not health or strength. This quick substitution test confirms that Strong is the correct antonym.

Why Other Options Are Wrong:
Weak: This word is similar in meaning to infirm and is therefore a synonym, not an antonym.
Supporter: This refers to a person who supports a cause or another person and has no opposite relationship to infirm.
Believer: This indicates someone who believes in a particular idea or faith and again does not contrast with physical weakness.

Common Pitfalls:
A common mistake is to confuse synonyms and antonyms, especially when both are present among the options. Some candidates may rush and choose weak because it feels familiar and close to the word infirm, without carefully reading that an opposite is required. Another pitfall is to select an unrelated word simply because it seems sophisticated or uncommon, even though it does not express the opposite meaning. To avoid this, it is important always to confirm whether the question is asking for a similar meaning (synonym) or an opposite meaning (antonym).

Final Answer:
The word that is opposite in meaning to INFIRM is Strong.