certify Get Printable Handwriting (cer-ti-fy) 3 syllables Rhymes Learn It! Spelling Test Definition verb. 1 to affirm the accuracy or certainty in a formal manner; confirm 2 to formally endorse or guarantee. Example Sentence The doctor will sign the paper to certify the health of his patient. Synonyms accredit; approve; endorse; qualify Antonyms deny; disavow; discredit Rhymes Three Syllable Rhymes (1) certify Four Syllable Rhymes (1) decertify Share with your friends: