n. An alum who graduated a significantly long time ago. Crust begins accreting on a graduate at the moment of Commencement. The longer a person has been out of Williams, the crustier he or she is.
(1) an alum is technically "crusty" when all the classes he or she knew at Williams have graduated. (ie: the '02's are now officially crusty because the last class they knew, '05's, recently graduated.)
adj. Having crust.
Used primarily in the Odd Quad, to apply to Odd Quadders (note that even Crusties are still Odd Quadders. Once an Odd Quadder, always an Odd Quadder).
Not to be confused with Kraftee.