Triggered means: Originally a clinical term for a trauma response; now used loosely to describe someone reacting strongly to something. Has become a culture-war flashpoint, where deploying "triggered" mockingly is. It has drug-related associations; worth a calm conversation about which side of the topic your teen is on. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.