[curtking]

Merriam-Webster recognizes it, though they do consider it slang:

Main Entry: dis
Pronunciation: 'dis
Function: transitive verb
Inflected Form(s): dissed; dis·sing
Etymology: perhaps short for disrespect
Date: 1986
1 slang : to treat with disrespect or contempt : INSULT
2 slang : to find fault with : CRITICIZE

Used in a sentence:
Please refrain from dissing the original poster because you're anal-retentive about word usage.

[Puppage]

Be sure to use that word(s) to show the world your intelligence.

because you're anal-retentive about word usage.

Oh, good. Name calling...yet ANOTHER display of intelligence. Just fill 'er up. And, check the oil while you're at it.

Sure, I'll even take fries wit dat, yo.