I learn that 'diss' is a shortened version of "disrespect"
Urban Dictionary: diss
For example, try to diss me, man.
What's the opposite of it?
I searched 'spect' as shorthand for 'respect'.
Nevertheless, it does not feel as strong and smart as 'diss'
Note:
'Diss' is a extremely popular in China as cyberspeak for joking with each other.
Best Answer
My first thought was to give someone props:
That's well-known here in the US. There's a relevant post on ELU: What's the etymology of “props”?
Notice that props itself is not used as a verb in this sense. We don't *prop or *props someone to mean that we praise them.