In this antonym question, select the word which is most opposite in meaning to "pilferer", that is, a petty thief.

Introduction / Context:
The word "pilferer" refers to someone who steals small amounts or petty items, usually secretly and repeatedly. It is a type of thief. In this antonym question, you are asked to choose the word whose meaning is most opposite to this, that is, a word that represents an individual or group whose role is to prevent or punish theft rather than commit it. Such questions help test your understanding of both word meanings and real world roles.

Given Data / Assumptions:

• "Pilferer" means a petty thief, someone who steals small things.
• The options are "sniper", "punk", "lifter", "police", and "robber".
• We must choose the best opposite in normal social and legal contexts.

Concept / Approach:
In vocabulary questions about opposites, the antonym does not always have to be a direct logical opposite, but rather the most appropriate contrast in meaning or role. A pilferer breaks the law by stealing; the group that is socially and legally responsible for catching thieves and preventing theft is the police. Therefore, "police" functions as the best conceptual opposite to "pilferer". Other options are either types of wrongdoers or slang terms without an opposite role relationship.

Step-by-Step Solution:
Step 1: Fix the meaning of "pilferer" as "a petty thief". Step 2: Consider "police". This word refers to the official law enforcement body that works to catch thieves and protect property. Step 3: Compare with "sniper". A sniper is a specialist shooter, often in military or criminal contexts, and is not the opposite of a thief. Step 4: Compare with "punk". "Punk" is informal slang that can refer to a troublemaker or youth subculture but has no clear semantic relationship as an opposite to "pilferer". Step 5: Compare with "lifter". In slang, "lifter" can also mean "thief", especially a shoplifter, so it is similar in meaning, not opposite. Step 6: Compare with "robber". A robber is another kind of thief, typically using force or threat, so again this is similar, not opposite. Step 7: Only "police" clearly stands in opposition to the role of a thief in society.

Verification / Alternative check:
Think of the simple pairings we use in everyday life: thief–police, criminal–police officer, lawbreaker–law enforcer. We do not naturally pair thief with sniper or thief with punk as opposites. In a story, if a pilferer is introduced, the natural opposite character is the police officer trying to catch him. This narrative and real world understanding confirms that "police" is the most suitable antonym among the given choices.

Why Other Options Are Wrong:
"Sniper" is a different type of dangerous person but not a law enforcer. "Punk" is vague slang and does not systematically oppose the idea of thief. "Lifter" and "robber" are both near synonyms for thieves and thus clearly not antonyms. Choosing any of these would show misunderstanding of the role based contrast the question is asking for.

Common Pitfalls:
Some students may look for a purely dictionary based direct opposite and feel unsure because no option is labelled "law enforcer". Others may be attracted to "lifter" or "robber" simply because they recognise them as crime words and do not carefully read that the question asks for an antonym, not a synonym. Always check whether the question is asking for a similar meaning (synonym) or opposite meaning (antonym) before you start eliminating options.

Final Answer:
The best antonym of "pilferer" among the options is police.