Diss not dis.
Only the folks who need to use urban dictionary or Wikipedia to define it thinks it's short for disrespect. If you're dissing somone, youre dismissing them. And the galaxy s7 keyboard has a mind of its own. I don't always catch the change it makes to words when typing fast or longer post; if I don't edit it before the time limit, it's stuck. It doesn't like emcee either so I just have to type MC.
But diss in the hip-hop slang has always been spelled 'diss'.
Sorry for the confusions...my bad.
ETA: to add to the confusion....you can also 'son' someone which is disrespect but not really a diss. If you 'son' them in their head aka mush, you're asking for a fight. But you can also call someone 'son' which is not disrespectful. Then again you can call someone your 'son' and that's the highest level of disrespect.

I sometimes wish the internet didn't open up hip-hop/urban/AAVE so much. Lol.