Waswas
Waswas (in Arabic وسوس) in Islam is a term for "whispers from Shaytan". When a Muslim has some thoughts against Islam, he disregards them as waswas - a voice of Shaytan.
Waswas in the Qur'an
The Arabic word وسوس (waswas) in various forms appears 5 times in the Qur'an.
The first two refer to the story of Adam and Eve. The fa- prefix means "but" or "then".
Then one time it's a persons soul which whispers. The tu- simply indicates present tense, 3rd person, feminine, singular verb.
And two times in a short sura 114. The al- indicates definite article (before a noun). The yu- indicates present tense, 3rd person, singular, masculine verb.
Say: I seek refuge in the Lord of men,
The King of men,
The god of men,
From the evil of the retreating whisperer (ٱلْوَسْوَاسِ, al-waswasi)
Who whispers (يُوَسْوِسُ, yuwaswisu) into the hearts of men,
From among the jinn and the men.