Is Imperturbableness a Word?

A stable, calm state of the emotions: aplomb, balance, collectedness, composure, coolness, equanimity, imperturbability, nonchalance, poise, sang-froid, self-possession, unflappability.

What is another word for imperturbability?

Some common synonyms of imperturbable are collected, composed, cool, nonchalant, and unruffled.

What is a word for not bothered?

Cheerfully unconcerned about the future or things in general. unconcerned. carefree. untroubled.