I'd probably get it if I understood what the "P" word means 
Like you, I was unsure of the meaning, despite the best efforts of the puppy dog, trying to put me off the scent with "Prunes", it has nothing to do with purging at all.
I confess that I had to look it up,
but here goes...
Pejorative comes from the Latin pejoratus, "made worse", and made a surprisingly late entry in written English, 1882, probably deriving from a contemporary French usage, p?joratif. [1]. It is so frequently spelled as perjorative that the Oxford English Dictionary website contains a FAQ entry about this spelling.
A word or phrase is pejorative if it implies contempt or disapproval. The adjective pejorative is synonymous with derogatory, derisive, and dyslogistic. When used as an adjective, pejorative has two meanings: (1) tending to make or become worse, and (2) tending to disparage or belittle. [1] When used as a noun, pejorative means "a belittling or disparaging word or expression". [2] Since meanings change over time, an up-to-date dictionary should be consulted for information on specific words.
