In English vocabulary, which of the following words best expresses the meaning of "Arbitrary" (based on personal whim or random choice rather than any reason or system)?

Introduction / Context:
Arbitrary is a common word in legal, political, and academic writing. It usually carries a negative sense that a decision or action is not based on any clear rule or reason, but only on personal choice or chance. This question asks you to select the word that best captures that idea.

Given Data / Assumptions:

• The word given is Arbitrary.
• Option A: Methodical.
• Option B: Penetrable.
• Option C: Random.
• Option D: Artful.
• We assume the usual meaning: based on random choice or personal whim, not on reason.

Concept / Approach:
An arbitrary decision is one that does not follow a logical pattern or rule; it can seem random and unpredictable. Hence, random is the closest simple synonym. Methodical is the opposite: it means done according to a system or method. Penetrable refers to something that can be entered or understood. Artful suggests skill or cleverness, especially in a tricky way. None of these except random matches the core idea of lacking reason or system.

Step-by-Step Solution:
Step 1: Fix the meaning of arbitrary as based on whim or chance rather than reasoned principles.Step 2: Compare this with random, which describes something happening without definite pattern, plan, or reason.Step 3: Recognise that arbitrary decisions often appear random to those affected, because they do not follow clear rules.Step 4: Examine methodical, which is carefully ordered and systematic, the very opposite of arbitrary.Step 5: Examine penetrable and artful; they are unrelated in meaning and do not express lack of system. Therefore, random is the best match.

Verification / Alternative check:
Think of sentences from news reports: The protesters complained of arbitrary arrests, meaning arrests made without clear legal reasons, seemingly at random. If we substitute random arrests, the meaning is very similar. In contrast, methodical arrests would mean they followed a careful plan, which is not what arbitrary implies. This confirms the closeness in meaning between arbitrary and random.

Why Other Options Are Wrong:
Methodical suggests careful planning and order, which is almost the opposite of arbitrary. Penetrable describes what can be passed through or understood and has nothing to do with reason or randomness. Artful means skillful or crafty, often with hidden cleverness; it does not convey the sense of lacking system or being based purely on whim.

Common Pitfalls:
Some students may confuse arbitrary with authoritarian or harsh, because arbitrary decisions are often criticised in political contexts. However, the core meaning is about the lack of reason or rule, not necessarily about severity. Keeping a simple pair in mind—arbitrary ≈ random decision, methodical ≈ systematic decision—can help you remember the correct sense.

Final Answer:
The word that best expresses the meaning of Arbitrary is Random, so option C is correct.