The word(s) "plain" appears 82 time(s) in 82 verse(s) in Quran in Muhammad Pickthal translation.

(31) And say: Lo! I, even I, am a plain warner,

(32) And the idolaters say: Had Allah willed, we had not worshipped aught beside Him, we and our fathers, nor had we forbidden aught without (command from) Him. Even so did those before them. Are the messengers charged with aught save plain conveyance (of the message)?

(33) That He may explain unto them that wherein they differ, and that those who disbelieved may know that they were liars.

(34) With clear proofs and writings; and We have revealed unto thee the Remembrance that thou mayst explain to mankind that which hath been revealed for them, and that haply they may reflect.

(35) And We have revealed the Scripture unto thee only that thou mayst explain unto them that wherein they differ, and (as) a guidance and a mercy for a people who believe.

(36) Then, if they turn away, thy duty (O Muhammad) is but plain conveyance (of the message).

(37) And be not like unto her who unravelleth the thread, after she hath made it strong, to thin filaments, making your oaths a deceit between you because of a nation being more numerous than (another) nation. Allah only trieth you thereby, and He verily will explain to you on the Day of Resurrection that wherein ye differed.

(38) On that day we shall present hell to the disbelievers, plain to view,

(39) And leave it as an empty plain,

(40) He said: Verily ye and your fathers were in plain error.