The word(s) "disbelieving" appears 18 time(s) in 18 verse(s) in Quran in Muhammad Pickthal translation.

(11) The chieftains of his people, who were disbelieving, said: Lo! we surely see thee in foolishness, and lo! we deem thee of the liars.

(12) But the chieftains of his people, who were disbelieving, said: If ye follow Shu'eyb, then truly ye shall be the losers.

(13) Postponement (of a sacred month) is only an excess of disbelief whereby those who disbelieve are misled; they allow it one year and forbid it (another) year, that they may make up the number of the months which Allah hath hallowed, so that they allow that which Allah hath forbidden. The evil of their deeds is made fairseeming unto them. Allah guideth not the disbelieving folk.

(14) Go, O my sons, and ascertain concerning Joseph and his brother, and despair not of the Spirit of Allah. Lo! none despaireth of the Spirit of Allah save disbelieving folk.

(15) That is because they have chosen the life of the world rather than the Hereafter, and because Allah guideth not the disbelieving folk.

(16) And (all) that she was wont to worship instead of Allah hindered her, for she came of disbelieving folk.

(17) O ye who believe! When believing women come unto you as fugitives, examine them. Allah is Best Aware of their faith. Then, if ye know them for true believers, send them not back unto the disbelievers. They are not lawful for them (the disbelievers), nor are they (the disbelievers) lawful for them. And give them (the disbelievers) that which they have spent (upon them). And it is no sin for you to marry such women when ye have given them their dues. And hold not to the ties of disbelieving women; and ask for (the return of) that which ye have spent; and let them (the disbelievers) ask for that which they have spent. That is the judgment of Allah. He judgeth between you. Allah is Knower, Wise.

(18) Lo! We have shown him the way, whether he be grateful or disbelieving.