Certainty

The triliteral root yā qāf nūn (ي ق ن) occurs in the Quran 28 times.

People of certainty

(45:4) In your creation, and creatures that He disperses, are signs for people who are certain (Arab. يُوقِنُونَ, yūqinūna).

(51:20) In the earth are signs for those who are certain (Arab. لِلْمُوقِنِينَ, lil'mūqinīna).