casualness

noun
1
lack of care or thought; an apparent lack of care or thought
بی‌توجهی, بی‌خیالی, سهل‌انگاری, بی‌تفاوتی, بی‌مبالاتی
2
the quality of being calm and relaxed
آرامش, راحتی, بی‌تکلفی
The staff mixed professionalism and casualness.
3
the fact of not being formal
غیررسمی بودن, بی‌تکلفی, بی‌آلایشی
the casualness of dress found in most bars these days
4
the fact of not being permanent or regular
عدم دائمی بودن, موقتی بودن
the casualness of their friendship