1. not worry about something to excess or even at all
it's not nice, but I won't lose any sleep over it
When you ‘lose sleep’ over something, it implies that you are awake all night worrying about it or thinking about something. When you say you ‘won’t lose any sleep’ over something you are saying something isn’t a major concern or worth spending time worrying about. This is a casual expression used in both social and professional contexts. Similar in meaning to ‘it’s no big deal’, ‘don’t worry about it’ and ‘it’s no skin off my nose’.