Select the most appropriate antonym of the given word. Pernicious

Correct — B. Pernicious means harmful or destructive, often in a gradual, hidden way, as in a pernicious influence.

The antonym must mean not harmful. Innocuous is built for that: Latin in-, 'not', + nocuus, 'harmful'. An innocuous remark or substance does no harm → option (b).

Why the others are wrong

• (a)
  Harmful — Harmful is the plain synonym of pernicious. It is the pick for a candidate who answers the synonym question instead of the antonym one.
• (c)
  Virulent — Virulent means extremely harmful or poisonous, as in a virulent disease, or bitterly hostile. It is a stronger synonym of pernicious, not an opposite.
• (d)
  Noxious — Noxious means harmful or poisonous, as in noxious fumes. It comes from the same Latin family as innocuous, nocere, 'to harm', but lacks the in- that reverses it.

An antonym item asks you to reverse the word, so fix its sense first. Pernicious is harmful, often slowly or out of sight: a pernicious habit does damage you may not notice at once.

Harmful, Virulent and Noxious are all synonyms of pernicious. Innocuous is the option that turns it round.

The prefix does the work: in- negates nocuus, 'harmful'.

Key facts

• Pernicious means highly harmful or destructive, often in a gradual or subtle way.
• Innocuous means harmless: Latin in-, 'not', + nocuus, 'harmful'.
• Innocuous and noxious both trace back to Latin nocere, 'to harm'.
• Virulent means extremely harmful or poisonous, and also bitterly hostile.

Common traps

• Choosing Harmful by answering as if the item asked for a synonym
• Reading the in- of innocuous as intensifying, as it is in inflammable, when here it negates

No directly related past PYQ was found.