impervious.

1. Not allowing a substance to pass through or penetrate.

2. Not affected by an influence, argument, or pressure.

Use it for

Words that belong together

• impervious material
• impervious to water

On the page

The lining was impervious to the tested fluid.

Water gathered on the impervious surface.

Usage notes

Primary category: literary. Forms: Comparative more impervious; superlative most impervious where gradation is meaningful. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings.