Correct, "import" has a spelling change when adding the suffix -ant. The correct spelling of the adjective form is "important."
The word that has a spelling change when adding the suffix -ant is "comply". When the suffix -ant is added to the base word "comply", the letter "y" is changed to "i". This is a common spelling change rule where a final "y" becomes "i" when adding a suffix that begins with a vowel sound. So, the correct word is "compliant".
