No, it is not formal. It is used in every day life. She's a procrastinator. <-- correct She always procrastinates (things), especially when it comes to doing household chores. Corrections: You don't really need to use the word "things". "Especially" sounds more natural in this sentence. "when it comes to doing..."

Okay even better. I will write it down in my list. Well, I can still improve my vocabulary then. Thank you.

Mojave is correct. It is used every day. Feel free to use it.

Okay, I am not a native speaker, but I had never heard or this word. My English is reasonably advanced, probably the same as yours? I would not use it. But, okay, what do I know.