The opposite of negligence. With negligence, someone acts in a way inconsistent with his duty and that results in a harm to another person that the actor did not intend. With posligence, someone acts in a way, consistent or inconsistent with his duty, that nevertheless results in a good to another person that the actor did not intend. An example: Jones, while driving recklessly, crashed on the property of Smith. The crash causes Smith to attend to the accident, whereupon he finds a buried treasure and becomes exceedingly wealthy. Another example: Jones visits Smith in the hospital to comfort him. Smith improves as a consequence of Jones' charity, but Smith's wife is also moved by the Jones' act, even though Jones did not intend that end for Smith's wife.
I invented this word over the weekend while reading about the Principle of Double Effect.