Failure to perform tongue-action between a woman's legs after agreeing to do so as part of a contract.
A lot of guys want to "do it" just with their hoo-haws, so whenever there is an offer to perform cunnilingus as "payment" for said "ultimate favor", perhaps the gal should always half-expect a derelicktion of duty to occur!
n. software that is no longer sold or supported by the original publisher / developer, often found as free downloads on the internet because it cannot be obtained elsewhere. Not legal, but often seen as morally acceptable because the company that made it is no longer selling the title, nor releasing it as freeware, therefore abandonware is "keeping the gamealive", so to speak.
Doom II is not abandonware because idstill sells it, while The Incredible Machine is not sold, therefore is abandonware.