In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

Imaam Muhammad Ibn Saaleh al-Uthaymeen [rahimahullaah] said:

Knowledge (Ilm) is to comprehend the reality of something as it truly is, with certainty.

The levels of comprehension are six:

[Al ‘Ilm – Knowledge], which is to comprehend the reality of something as it truly is, with certainty.

[Al Jahlul Baseet- slight ignorance], which is absence of full comprehension.

[Al Jahlul Murakkab-, Aggravated/compounded ignorance], which is to comprehend something in a way contrary to its true reality.

[Al Wahm – Delusion], which is to think that one comprehends something despite the presence of that which should cause you to realize that you are incorrect.

[Ash Shakk- Doubt], which is to think that you comprehend something, yet you are aware of something contrary to it which you think has the same possibility of being the truth.

[Dhann – Preponderant belief], which is comprehension of something, despite the presence of something which is contrary to it, but which is less likely to be true.

[Source: Sharh Usool Ath-Thalaatha- Explanation of the three fundamental principles. English Translation pages 37. By Shaikh Abu Talhah (may Allaah have mercy upon him and his wife Aameen)]