"everclear" means: Any home-brewed distilled grain alcohol, especially one with a very high concentration of alcohol (such as 90-some percent, that is, 180-som.... There is a drug-related reference, so this is one worth noticing without overreacting. Many teens encounter such vocabulary through music, film and friends without any direct involvement. A neutral, curious conversation about where they heard the term and what they understand by it is far more useful than a confrontation. Watch for repeated context, not a single word.