self-own

A 'self-own' is when someone tries to mock or own someone else but ends up embarrassing themselves instead — accidentally proving the opposite of what they meant, or revealing something unflattering about themselves. 'That tweet was a self-own' = 'they undermined their own argument'. Common in political and online discourse. If your teen uses it, they are laughing at someone's accidental self-sabotage. Harmless observational vocabulary.

'Self-own' is internet and political-discourse English for an act of trying to insult or 'own' someone else but accidentally damaging one's own reputation or argument — for example, by inadvertently proving the opposite point or revealing something unflattering. Register: informal, social media and political journalism. In formal writing use 'inadvertent self-undermining' or 'rhetorical own goal'. A common learner mistake is to confuse 'own' (verb, slang = to defeat decisively) with 'own' (verb, standard = to possess); the slang sense is the relevant one here.