The word(s) "foolish" appears 10 time(s) in 10 verse(s) in Quran in Mohsin Khan translation.

(1) And (remember) when Musa (Moses) said to his people: "Verily, Allah commands you that you slaughter a cow." They said, "Do you make fun of us?" He said, "I take Allah's Refuge from being among Al-Jahilun (the ignorant or the foolish)."

(2) And give not unto the foolish your property which Allah has made a means of support for you, but feed and clothe them therewith, and speak to them words of kindness and justice.

(3) Allah accepts only the repentance of those who do evil in ignorance and foolishness and repent soon afterwards; it is they whom Allah will forgive and Allah is Ever All-Knower, All-Wise.

(4) Indeed lost are they who have killed their children, foolishly, without knowledge, and have forbidden that which Allah has provided for them, inventing a lie against Allah. They have indeed gone astray and were not guided.

(5) The leaders of those who disbelieved among his people said: "Verily, we see you in foolishness, and verily, we think you are one of the liars."

(6) (Hud) said: "O my people! There is no foolishness in me, but (I am) a Messenger from the Lord of the 'Alamin (mankind, jinn and all that exists)!

(7) And Musa (Moses) chose out of his people seventy (of the best) men for Our appointed time and place of meeting, and when they were seized with a violent earthquake, he said: "O my Lord, if it had been Your Will, You could have destroyed them and me before; would You destroy us for the deeds of the foolish ones among us? It is only Your Trial by which You lead astray whom You will, and keep guided whom You will. You are our Wali (Protector), so forgive us and have Mercy on us: for You are the Best of those who forgive.

(8) Show forgiveness, enjoin what is good, and turn away from the foolish (i.e. don't punish them).

(9) And the (faithful) slaves of the Most Gracious (Allah) are those who walk on the earth in humility and sedateness, and when the foolish address them (with bad words) they reply back with mild words of gentleness.

(10) 'And that the foolish among us [i.e. Iblis (Satan) or the polytheists amongst the jinn] used to utter against Allah that which was an enormity in falsehood.