"nosh off" means: A British slang term with two distinct meanings: the original/primary sense is to eat something (from 'nosh' meaning food or to eat), while.... The term has a sexual reference, so parents may want to know the context in which a child uses or hears it. In most cases it is part of normal teenage curiosity rather than a concrete worry. A short, non-judgemental conversation about consent, respect and online safety is usually the best response. Look at the wider pattern of behaviour, not the one word.