However, it's important to note that "reason" is a root word, not a word with a suffix attached. It's a word in its own right, and it has no suffix.
If you're looking for words with suffixes related to the concept of reason, here are a few examples:
* -able: Reasonable (capable of being reasoned with)
* -ing: Reasoning (the act of thinking logically)
* -ed: Reasoned (thought out logically)
* -al: Rational (based on reason)
* -less: Reasonless (without reason)