stain

Concise Oxford English Dictionary © 2008 Oxford University Press:
stain/steɪn/

▶verb

• 1 mark or discolour with something that is not easily removed.

• 2 damage (someone's or something's reputation).

• 3 colour with a penetrative dye or chemical.

▶noun

• 1 a stubborn discoloured patch or dirty mark.

• 2 a thing that damages a reputation.

• 3 a dye or chemical used to colour materials.

  ■ Biology a dye used to colour organic tissue so as to make the structure visible for microscopic examination.

• 4 Heraldry any of the minor colours used in blazoning and liveries.

– derivatives
stainable adjective,
stainer noun.

– origin ME: shortening of archaic distain, from OFr. desteindre ‘tinge with a different colour’.