We are taught in school that words are made from other words. The words that words are made from are called "root words." Damnation is made from adding -ation to damn. Therefore damn is the root word of damnation.
Chair does not have any components from any other word, so it doesn't have a root. Chair is its own root.
It doesn't matter if the word is a noun or a verb. Damn is the root of Damning as well as damnation. Both nouns and verbs can have or not have prefixes and/or suffixes.
Don't hurt me.