Incarnadine

[Sarah]

Flesh-colored; of a carnation or pale red color. [Obs.]Lovelace.

[Sarah]

A rather cool word which means to dye something blood-red or for it to turn red (in the case of Macbeth)...

However, before Macbeth it originally meant a pale pink colour (actually, it meant flesh coloured, but 'tis close enough) and 'twas used as an adjective. In Macbeth it is used as a verb, in fact, it's the first time for it to be used in this way.