"adulting fail" means: A moment of spectacular, usually public incompetence at the basic mechanics of adult life — the kind of thing you're technically supposed to.... This is a fairly neutral word with no inherent risk attached. There is no real cause for parental concern; it is descriptive vocabulary rather than something dangerous. If your child uses it, context will usually make the meaning clear. A brief, curious question about where they heard it is generally enough to know whether to follow up.