[WPI: from the DEC acronym CUSP, for 'Commonly Used System Program', i.e., a utility program used by many people]
adj. 1. (of a program) Well-written.
2. Functionally excellent. A program that performs well and interfaces well to users is cuspy.
3. [NYU] Said of an attractive woman, especially one regarded as available. Implies a certain curvaceousness.