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

(41) Say: I am not the first of the apostles, and I do not know what will be done with me or with you: I do not follow anything but that which is revealed to me, and I am nothing but a plain warner.

(42) And mention the brother of Ad; when he warned his people in the sandy plains,-- and indeed warners came before him and after him-- saying Serve none but Allah; surely I fear for you the punishment of a grievous day.

(43) And the earth, We have made it plain and cast in it mountains and We have made to grow therein of all beautiful kinds,

(44) Therefore fly to Allah, surely I am a plain warner to you from Him.

(45) And do not set up with Allah another god: surely I am a plain warner to you from Him.

(46) Allah indeed knows the plea of her who pleads with you about her husband and complains to Allah, and Allah knows the contentions of both of you; surely Allah is Hearing, Seeing.

(47) Say: The knowledge (thereof is only with Allah and I am only a plain warner.

(48) He said: O my people! Surely I am a plain warner to you:

(49) Again on Us (devolves) the explaining of it.