Simply "asshole" spelled backwards. It's meant to be funny cause it sounds spanish but anyone who speaks spanish will have no idea what your talking about.
Last night I was chillin' at the club and some El Ohssa stepped on my Pumas.
It's 'oh, shit!' fast, and cut off into 'oh, sh--!' or a way to sarcastically make a comment to/about someone trying to be intimidating. (: people say it without even knowing so it might as well be a word!
kid: "back up!"
person (talking to friend): "OHSH! i'm SOOO scared" (sarcasm)
person: OHSSH!
random kid: what does that me?
person: oh shit!
OpsSec, OPSSEC, or Opssec. Is AOL Operations Security Team. They take care of SecurID and passwordissues for employees. While also maintaing account security of elite and privileged accounts.