diss

Etymology 1

Originated in Jamaican English or African American Vernacular English, probably originally a clipping of disrespect or disparage, both from the prefix dis-, ultimately from Latin dis-.

verb

1. (slang) To put (someone) down, or show disrespect by the use of insulting language or dismissive behaviour.
   When a journalistic rival tries to "dis" you And to prejudice you in the public's eyes. Don't stigmatise his charges as a "tissue Of palpable, unmitigated lies." 1905, 10 December, The Sunday Times (Perth), "A New Word", page 4

noun

1. (slang) An insult or put-down; an expression of disrespect.

Etymology 2

Clipping of dissertation

noun

1. (slang) Dissertation.
   I've been wondering what happens if I fail my diss. I know i'm allowed to fail 60 credits but I don't think that includes the diss. 2012-04-05, shkbop9190, “Failing a Dissertation”, in The Student Room Forums, retrieved 2016-12-01

Etymology 3

From Arabic دِيس (dīs).

noun

1. Ampelodesmos mauritanicus syn. Ampelodesmos tenax, a reedy grass used for cordage.