informality

noun
1
relaxed and friendly behaviour or speech that does not follow strict rules of how to behave or do something
غیررسمی, بی‌تکلفی, خودمانی, صمیمیت
opposite formality(3)
2
a style that does not follow strict rules
غیررسمیت, بی قاعده بودن
His early paintings display great informality and lightness of touch.