1979, coined from pal (n.) + alimony. Popularized, if not introduced, during lawsuit against U.S. film star Lee Marvin (1924-1987).
: a much-heralded palimony suit
Money awarded, property shared, etc, when an unmarried couple separate (1979+)
[fr pal plus alimony; coined for or at least popularized by a lawsuit against the film star Lee Marvin]