Loungewear is defined as comfortable and casual clothing that is versatile for relaxing, working from home or venturing out for an indulgent brunch.
It's a cross between sleepwear and athleisure as it fits loosely enough to be cozy while also being tailored enough to be chic in style.
Loungewear is casual attire that makes you feel highly comfortable while keeping an appropriate look.
So loungewear is not out-of-bed pajamas that are way too cozy and casual. It is also not jeans which is less casual and comfortable than the loungewear.