Rivalsome

Strength of numbers against foes, in a more populous and rivalsome world, was an added if not paramount consideration.

Source: wiktionary

But perhaps most significantly, Java's Sun ties and VRML's SGI ties affiliated them with two of the Valley's most famously rivalsome rivals.

Source: wiktionary

Opening in the fruit naming division of the Eden Corporation with a professionally rivalsome Adam and Eve, and a curiously jaunty God, Eve finds herself unable to resist the charms of a rare apple, and the pair are cast out of the organisation and ordered to seek a new apple to replace the collectors item which Eve has just scoffed.

Source: wiktionary