impervious

Imagine a sleek, waterproof raincoat. It's impervious to rain - the water simply beads up and rolls off. That's the core idea. Something impervious does not let something else get in, and it is not easily harmed by it. It can be physical, like that coat, or more figurative. A politician might seem impervious to criticism, meaning negative comments do not bother them much. A fortress might be impervious to attack, meaning it is so strong that attacks do little to it. Think of something that stays untouched even when pressure is applied - that is often what impervious suggests.

The word impervious describes something that is unable to be penetrated, damaged, or affected by something else. It comes from the Latin words "im-" (not) and "pervius" (passable), literally meaning "not passable."

Originally, it referred to things that could not be physically penetrated, like a waterproof material. "The roof was impervious to leaks after the repairs." But over time, impervious expanded to describe resistance beyond just physical barriers.

You might say someone is "impervious to flattery" if they do not let compliments influence them. Or that a person seems "impervious to reason," meaning logic does not change their mind. A hardened criminal might be described as impervious to guilt or remorse, suggesting a lack of emotional response.

In science, impervious can refer to materials that don't allow fluids or gases to pass through them—like certain types of clay soil. It also appears in geology when describing layers of rock that prevent water from seeping through.

So, whether it's a physical barrier, an emotional shield, or a stubborn resistance to change, impervious describes something that stands firm and remains unaffected by external forces.