staining

verb

1. 1

   To discolour.

   “armour stained with blood”

2. 2

   To taint or tarnish someone's character or reputation

3. 3

   To coat a surface with a stain

   “the stained glass used for church windows”

4. 4

   To become stained; to take a stain.

5. 5

   To treat (a microscopic specimen) with a dye, especially one that dyes specific features

6. 6

   To cause to seem inferior or soiled by comparison.