In the following vocabulary question, choose the word which best expresses the meaning of the given word IMPECCABLE in standard English usage.

Introduction / Context:
This question tests your knowledge of high level adjectives used to describe quality or behaviour. The word impeccable is often used to describe something that is perfect, without any fault or error, such as impeccable manners or impeccable performance. You must choose the option that most closely matches this meaning. The options include several adjectives with different senses, so careful comparison is required.

Given Data / Assumptions:

• The target word is impeccable.
• The context is general English vocabulary for competitive exams.
• Options are inoffensive, harmless, important, and faultless.
• The correct answer should convey the idea of perfection and absence of faults.

Concept / Approach:
Impeccable describes something that is so good that it cannot be criticised. Faultless describes something that has no faults or mistakes, which is a direct match. Inoffensive means not likely to offend, harmless means not causing harm, and important means significant. None of these three captures the idea of being perfect or error free. Therefore, faultless is the most accurate synonym among the given options.

Step-by-Step Solution:
Step 1: Recall the definition of impeccable as perfect or without flaws. Step 2: Examine option d, faultless, which means having no faults or errors. Step 3: Compare impeccable and faultless in sample phrases, such as impeccable service and faultless service, noticing that both convey the same idea. Step 4: Consider inoffensive, which focuses on not causing offence rather than on being perfect. Step 5: Consider harmless, which emphasises lack of harm, not absence of flaws. Step 6: Consider important, which refers to significance or influence, not to quality or flawlessness. Step 7: Decide that faultless is the best synonym for impeccable in this context.

Verification / Alternative check:
Test the options in a simple sentence: Her impeccable performance impressed everyone can be rewritten as Her faultless performance impressed everyone without changing the essential meaning. However, saying her harmless performance or her inoffensive performance sounds odd and does not convey excellence. Her important performance shifts the meaning entirely. This confirms that faultless is the closest match.

Why Other Options Are Wrong:
Inoffensive is wrong because something may be inoffensive yet still be mediocre or flawed. Harmless is wrong because it refers to safety, not to perfection. Important is wrong because it measures significance, not quality. None of these words describe something that is perfect and cannot be criticised, which is what impeccable conveys.

Common Pitfalls:
Learners may confuse impeccable with impressive or important because it often appears in praise, but the key idea is absence of faults, not mere significance. Another common error is to choose inoffensive because it sounds formal, but its meaning is narrower and unrelated to perfection. Always focus on the core meaning of the target word and check which option preserves that meaning most completely.

Final Answer:
The word that best expresses the meaning of IMPECCABLE is FAULTLESS.