The word(s) "plain" appears 49 time(s) in 49 verse(s) in Quran in Muhammad Habib Shakir translation.

(21) And they who give associates (to Allah) say: If Allah had pleased, we would not have served anything besides Allah, (neither) we nor our fathers, nor would we have prohibited anything without (order from) Him. Thus did those before them; is then aught incumbent upon the apostles except a plain delivery (of the message)?

(22) And on the day when We will raise up in every people a witness against them from among themselves, and bring you as a witness against these-- and We have revealed the Book to you explaining clearly everything, and a guidance and mercy and good news for those who submit.

(23) And We have made the night and the day two signs, then We have made the sign of the night to pass away and We have made the sign of the day manifest, so that you may seek grace from your Lord, and that you might know the numbering of years and the reckoning; and We have explained everything with distinctness.

(24) And certainly We have explained for men in this Quran every kind of similitude, but most men do not consent to aught but denying.

(25) And the day on which We will cause the mountains to pass away and you will see the earth a levelled plain and We will gather them and leave not any one of them behind.

(26) And certainly We have explained in this Quran every kind of example, and man is most of all given to contention.

(27) Then leave it a plain, smooth level

(28) Say: O people! I am only a plain warner to you.

(29) I am naught but a plain warner.

(30) In plain Arabic language.