Definition of grues:
(n) :
A fictional man-eating predator that dwells in the dark.
(n) :
(Scotland) A shiver, a shudder.
(n) :
Any byproduct of a gruesome event, such as gore, viscera, entrails, blood and guts.
(v) :
(intransitive, archaic except Northern England, Scotland) To be frightened; also, to shudder with fear; to quake, to tremble.
(adj) :
(philosophy) Of an object, green when first observed before a specified time or blue when first observed after that time.
(adj) :
(linguistics) Of a single color inclusive of both green and blue as different shades, used in translations from languages such as Old Welsh and Old Chinese that lacked a distinction between green and blue.