Clipping of proper (as in "proper respect" or "proper recognition") + -s.
Meanings
(plural, plural-only, slang) Respect for, or recognition of, another person; an expression of approval or a special acknowledgment; accolades; praise.
I also want to acknowledge state senator Elaine Alquist who is here... I always want to give her her props. 2007, Barack Obama (speaking at Google on November 14, 2007Candidates at Google: Barack ObamaPublic Policy Blog. Candidates at Google: Barack Obama)
I've got to give props to Roger for the way he handled that situation.