Verbs can act as nouns. They are gerunds. I think the fighting in Iraq is awful. I am not great at grammar. Here the fighting is a thing. There is no action. Think would be the verb, and the fighting is a thing.

>> there are many words like them. << Excellent. Indeed, this is a big concept in English. Then it means it's left for yourself to figure out. This is something you must learn by yourself, you must "feel" then come to be used to. Let alone the typical gerund use and as adjectives.

The -ing form of a verb like "fight" when used as a noun is called a gerund. Yes, this is common.