It's not a word, but it doesn't help that the English language is inconsistent on this (and so many other rules). Action is a noun. You're supposed to add "-ing" to verbs. Running, walking, reading, etc. are words. Kittening, lamping, etc. are nonsense.
Then it doesn't help that some nouns are also sometimes the verbs for that object. "I'm going to phone someone."
The corporate world is responsible for turning nouns into verbs: chairing, hoteling, and now actioning. So while you can get away with using these words in the office, you sound like an idiot using them in real life.