In the following question, choose the word which is opposite in meaning to the given word GREGARIOUS.

Introduction / Context:
This vocabulary problem asks for an antonym, that is, a word opposite in meaning, of the adjective gregarious. Knowing antonyms is especially useful when reading descriptions of personalities, social behaviour and habits. Gregarious is commonly used in social science texts and everyday English to describe people who enjoy the company of others.

Given Data / Assumptions:

• The target word is GREGARIOUS.
• The answer choices are UNSOCIABLE, UNSYMPATHETIC, UNGRATEFUL, UNATTRACTIVE and UNHELPFUL.
• We assume that the context is describing a person's social nature.
• Gregarious generally means fond of company, sociable, or living in flocks or groups.

Concept / Approach:
Gregarious refers to someone who likes being with other people, enjoys social gatherings and prefers company to solitude. The opposite of this quality would be a tendency to avoid company, to be withdrawn or to dislike social interaction. The adjective unsociable captures that opposite. The other options relate to gratitude, sympathy, physical attractiveness or helpfulness, which are different traits and do not directly oppose sociability.

Step-by-Step Solution:
Step 1: Restate the meaning of gregarious as sociable and fond of company.
Step 2: Identify which option describes a person who is not sociable or avoids company.
Step 3: Notice that unsociable directly expresses a lack of sociability.
Step 4: Check that unsympathetic refers to lack of sympathy, which is a different quality.
Step 5: Confirm that ungrateful, unattractive and unhelpful do not relate to social preference and therefore cannot be true antonyms.

Verification / Alternative check:
Example sentences make the contrast clear: She is a gregarious person who loves parties versus He is an unsociable person who prefers to stay alone. The pair gregarious and unsociable clearly describe opposite ends of a social preference scale. In contrast, someone can easily be gregarious but unsympathetic, or gregarious and ungrateful, or gregarious but unattractive. These words measure different traits and are not direct opposites. Therefore unsociable best captures the antonym relationship.

Why Other Options Are Wrong:
Option B, unsympathetic, means lacking sympathy or compassion and relates to emotional understanding rather than social preference. Option C, ungrateful, is about not showing thanks or appreciation. Option D, unattractive, refers to physical appearance or lack of appeal. Option E, unhelpful, describes behaviour in terms of assistance, not sociability. None of these terms tell us whether a person likes company or tends to avoid it. Therefore they cannot be accepted as antonyms of gregarious.

Common Pitfalls:
Some candidates may choose any negative adjective starting with un, assuming that any negative trait could be opposite to a positive one. However, antonyms must be opposite in the same semantic field. A good habit is to first define the word in simple terms and then find an option that negates exactly that definition, rather than just sounding negative. For gregarious, defining it as sociable quickly leads to unsociable as the precise opposite.

Final Answer:
The word opposite in meaning to GREGARIOUS is UNSOCIABLE.