perquisite

1.) something additional to regular profit or pay, resulting from one's position or employment; esp. something customary or expected 2.) a tip or gratuity 3.) a privilege or benefit to which a person, institution, etc. is entitled by virtue of status, position, or the like; prerogative; right

Am Gods, pg. 327 AmPB

PERK. Not having read the entire entry, it sent me searching for prerequisite, because I'd been inspired to find the word mispronounced on the same terms as those two, which are not often mistaken. To thesaurus under "right," prerogative, often pronounced (incorrectly, as stated before, much to my annoyance) as "per-rogative." Had I read the entire dictionary entry, I would have found it.

[Further note, outside of the written version, for those reading: If that didn't make sense, merely think of it this way, which is how I saw it:
perquisite:prerequisite::per-rogative:prerogative
My mental discord came from the fact that the "per-rogative" is an all-too-common mispronunciation. The phonetic similarities triggered my search.]