Select the correct spelling of a word meaning 'undoubtedly true'.

Correct — A. Break the word into its parts: in- (not) + controvert (to dispute or deny) + -ible (able to be).

Something incontrovertible cannot be disputed, which is why it means 'undoubtedly true'.

The middle is spelt -vert-, as in convert and invert, and it keeps both its e and its r → option (a).

Why the others are wrong

• (b)
  Incontrovartible — Incontrovartible puts an a where the root has e. The root is vert, as in convert, divert and controversy.
• (c)
  Incontrovatible — Incontrovatible changes the e to a and drops the r. Without the r, the root vert disappears.
• (d)
  Incontrovurtible — Incontrovurtible writes u for e. Er and ur sound alike, as in her and fur, so anchor the vowel on controversy, a word you already spell with e.

All four options open Incontrov- and close -tible. Only the letters between change, so the item tests one syllable: vert.

Tie it to words you already spell. Controversy and controvert both spell contro-ver- with an e, and convert, invert and revert carry the same -vert-.

Once you see incontrovertible as in + controvert + ible, the e and the r are fixed.

Key facts

• Incontrovertible means not able to be denied or disputed.
• It is built as in- + controvert + -ible.
• Controvert means to deny the truth of something, or to argue against it.
• Convert, invert and revert share the root -vert-, from Latin vertere, 'to turn'.

Common traps

• Spelling the stressed syllable by ear, when er and ur sound alike, as in her and fur
• Dropping the r of vert, which removes the root the word is built on

No directly related past PYQ was found.