Informality (noun)

1. Lack of formality in behavior, dress, or language.
2. Casualness or informality in a situation.

Origin:

From informal + -ity, meaning the state or quality of being informal.

Examples:

1. The meeting had an air of informality, with people dressed casually.
2. He preferred the informality of working in a coffee shop over a formal office setting.
3. The informality of their relationship made it difficult to know what to expect.
4. Informality is the norm at the company, everyone addresses each other by their first name.
5. The informality of the wedding ceremony made it more personal and intimate.