What is prefix and/or suffix in the word "illogical"?

This word has both: a prefix "il-" and a suffix "-al"

This word is formed from a noun "logic". The suffix "-al" changes it to an adjective, the prefix "il-" is a negation, so the creation of this word can be written in 3 steps:

1. Starting from a noun "logic" meaning "the ordered way of thinking and reasoning"
2. Adding a suffix "-al" which changes the noun to an adjective "logic-al" meaning "in a way including logic and reasoning"
3. Final step is adding a prefix "il-" which is a way to negate the word: "il-logic-al" means "without any logical reasoning"