Someone who pushes past official limits in terms of expression and demeanor, serving to test the boundaries between what could nominally get one fired and what WILL get one fired. From the use of songbirds in mining, whose greater susceptibility to impure air causes them to expire first, serving as a warning to humans.
Did you see the chicks on Fred's screen savor? That dude is our HR Canary.
by jimmythegeek June 17, 2010