1.
If you are ~ to someone’s actions, you are not affected or influenced by them.
She seems almost ~ to the criticism from all sides...
ADJ: usu v-link ADJ, usu ADJ to n
2.
Something that is ~ to water, heat, or a particular object is able to resist it or stop it passing through it.
The floorcovering you select will need to be ~ to water.
= impermeable
ADJ: oft ADJ to n