In English vocabulary, which single word best describes "a person inclined to question or doubt accepted opinions"?

Introduction / Context:
This question belongs to the one word substitution category. It checks whether you can identify a concise term for a person who does not simply accept beliefs or opinions blindly, but instead questions or doubts them. Such vocabulary is valuable in discussions about science, philosophy, religion, and social issues, where attitudes toward accepted views play a central role.

Given Data / Assumptions:

• The descriptive phrase is "a person inclined to question or doubt accepted opinions".
• We must pick the best matching word from "Adherent", "Sceptic", "Zealot", and "Disciple".
• We assume standard British spelling, where "sceptic" is commonly used.
• The context is general English vocabulary for competitive exams.

Concept / Approach:
A person who questions or doubts accepted opinions, especially in religion or in science, is called a "sceptic" or "skeptic". This word stresses doubt and critical thinking. The other options all describe people who follow or strongly support beliefs, rather than questioning them. Therefore the correct approach is to contrast the idea of doubt with the idea of loyalty or enthusiasm and choose the word that clearly represents doubt.

Step-by-Step Solution:
Step 1: Identify the key idea in the phrase, which is the tendency to question and doubt accepted views.Step 2: Recall that "sceptic" refers to someone who is not easily convinced and requires evidence before accepting claims.Step 3: Examine the other options and see that "Adherent" and "Disciple" relate to following, while "Zealot" refers to extreme enthusiasm.Step 4: Match the phrase with "sceptic" because it is the only word focused on doubt.Step 5: Confirm with dictionary style meanings to make sure there is no ambiguity.

Verification / Alternative check:
Dictionaries define "sceptic" as "a person inclined to question or doubt accepted opinions" or "a person who doubts the truth of religion, particularly Christianity, or of important widely held beliefs". "Adherent" is defined as someone who supports or sticks to a particular party, person, or set of ideas. "Zealot" is a person who is fanatical and uncompromising in pursuit of their religious, political, or other ideals. "Disciple" is a follower or student of a teacher or leader. This shows clearly that only "sceptic" matches the phrase exactly.

Why Other Options Are Wrong:

• Option A "Adherent" describes someone who strongly supports a belief or leader, so it implies loyalty, not doubt.
• Option C "Zealot" refers to an excessively enthusiastic supporter, again the opposite of a doubter.
• Option D "Disciple" is a follower or student who learns from and usually accepts the teachings of a master, not someone who questions them.

Common Pitfalls:
Learners sometimes confuse "sceptic" with "cynic". A sceptic simply doubts and asks for evidence, while a cynic often believes that people are motivated purely by self interest and may have a negative or suspicious view of human motives. For exam purposes, it is important to keep these distinct definitions in mind so that you do not pick the wrong word when very similar descriptions are given.

Final Answer:
The one word substitute for "a person inclined to question or doubt accepted opinions" is "Sceptic".