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TOEIC Link Part 5: ingenious versus ingenuous

Ingenious means clever and inventive; ingenuous means innocent, frank, and unsophisticated. One letter separates them and the meanings barely overlap, so Part 5 uses the pair to test whether you read for meaning rather than for the familiar-looking word.

EnglishBlitz Team·

TOEIC Link Part 5: ingenious versus ingenuous

Ingenious and ingenuous differ by a single letter and look almost identical, but they describe opposite qualities. Ingenious means clever, inventive, resourceful; ingenuous means innocent, frank, unworldly. Because the two adjectives are so close in spelling, Part 5 can slot the wrong one into a blank and let a hurried reader pick the familiar shape rather than the meaning. For another pair separated mostly by spelling, see complement versus compliment.

The core rule: clever versus innocent

  • ingenious (adjective) = clever, inventive, cleverly designed or resourceful. The engineer devised an ingenious solution to the cooling problem. / It was an ingenious marketing campaign.
  • ingenuous (adjective) = innocent, candid, frank, and lacking guile or sophistication. Her ingenuous answer showed she had no idea the question was a trap. / He gave an ingenuous smile.

The clue is the quality being praised or described. Ingenious describes intelligence and invention — a design, a plan, a device, a solution that is remarkably clever. Ingenuous describes character — a person who is open, naive, and free of cunning. One is about smart thinking; the other is about an unguarded, trusting nature.

Why Part 5 likes this pair

The two words modify different kinds of nouns, so what the adjective describes usually decides the answer.

The team came up with an __ device that cut assembly time in half.

The blank describes a device praised for cleverness, so ingenious fits. A device cannot be innocent.

Investors were charmed by the founder's __ honesty about the risks.

Here the blank describes honesty that is frank and unguarded, so ingenuous is required.

Spotting the clue in the structure

Ask what the adjective is really praising:

  • It describes a plan, device, solution, method, or design admired for cleverness → choose ingenious (an ingenious design, an ingenious plan).
  • It describes a person, manner, smile, or remark that is innocent, frank, or naive → choose ingenuous (an ingenuous reply, an ingenuous newcomer).

A quick test settles most items: if you could swap in clever or inventive, you want ingenious; if you could swap in innocent or candid, you want ingenuous. For another pair where the noun being modified decides the answer, see eminent versus imminent.

Quick self-check

  1. Her __ design for a foldable stand impressed the judges. (ingenious — clever, inventive)
  2. The new intern's __ questions revealed how little he knew of office politics. (ingenuous — innocent, unworldly)

Takeaway

If the blank praises a clever, inventive plan, device, or solution, you need ingenious. If it describes a person or manner that is innocent, frank, and free of guile, you need ingenuous. Decide whether the sentence admires cleverness or describes innocence, and the single-letter gap stops being a trap. For a related adjective pair decided by meaning, see principal versus principle.