In this English vocabulary question on one-word substitutions, choose the single word that best expresses the meaning of the phrase "involving immoral or dishonourable actions and motives".

Introduction / Context:

This question checks your understanding of one-word substitutions and finer shades of meaning in English adjectives. You are given a descriptive phrase, "involving immoral or dishonourable actions and motives", and asked to choose a single word that best captures this sense. Such questions are common in competitive exams because they test both vocabulary depth and the ability to distinguish between similar sounding or related words.

Given Data / Assumptions:

- Phrase to be replaced: "involving immoral or dishonourable actions and motives".

- Options: "redoubt", "scrupulous", "immaculate", and "sordid".

- Only one option must closely match the negative moral sense expressed in the phrase.

- The correct answer should describe behaviour or motives that are morally dirty, shameful, or corrupt.

Concept / Approach:

The key words in the phrase are "immoral" and "dishonourable". These point to actions that are unethical, shameful, or corrupt. We should therefore look for an adjective that describes morally degraded or dirty behaviour. Among the options, "sordid" is well known for meaning morally foul, base, or involving dirty motives. The other options either describe positive moral qualities or have meanings unrelated to morality. Understanding these nuances allows us to select the most accurate word.

Step-by-Step Solution:

Verification / Alternative check:

To verify, we can try to substitute each option into example sentences. "He was involved in sordid deals" clearly means he engaged in morally shameful or corrupt activities. In contrast, "scrupulous deals" would imply careful honesty, the exact opposite. "Immaculate deals" would suggest perfect cleanliness or flawlessness, again opposite to immoral actions. "Redoubt" cannot even function grammatically in that sentence. Thus, only "sordid" fits both meaning and usage as a one-word replacement.

Why Other Options Are Wrong:

"redoubt" is a noun related to fortifications and has nothing to do with moral behaviour. "scrupulous" describes someone who is extremely careful to do what is right, so it is a positive moral adjective rather than a negative one. "immaculate" suggests purity and perfection, not corruption or dishonour. All three therefore oppose or ignore the idea of immoral or dishonourable motives, making them unsuitable as substitutes for the given phrase.

Common Pitfalls:

A common error is to choose a word based only on vague familiarity or sound, rather than on precise meaning. Some students may wrongly associate "immaculate" with something intense or dramatic and therefore think it is close to the phrase, even though its meaning is completely positive. Others might confuse "scrupulous" with "unscrupulous", which has the opposite meaning. Building a strong vocabulary requires not just memorising words but also paying attention to context and whether the word carries a positive, negative, or neutral connotation.

Final Answer:

The best one-word substitute for the phrase is "sordid", which means involving immoral, dishonourable, or corrupt actions and motives.