A message indicating that a user from a network has left/exited.

What you don't want to see when you are talking to your girlfriend/boyfriend.
Tom: hey babe
Tom: you there?!
Tom: hellloooooooo?!!?
Tom: ARE YOU STILL THERE?!?!?!?!?!
\Tina has signed off.
\The message has not been sent because the recipient is currently unavailable.

by Godknown March 25, 2006
A term to describe the act of leaving an area, or agreeing with a project.
Contributor "Loxi" is permanently signing off from the Urban Dictionary today so she can concentrate on delivering her special brand of humor to the unsuspecting spouse, kids, and people in the neighborhood - and to allow other dictionary contributors to have their say.

Long may Urban Dictionary reign!
by Loxi July 23, 2009
This is someone's favorite catchphrase
This is what he believes will help him get to space
Aaron: I am going to be signing off!
European: you are my idol and yh Aaron Thomas signing off!!!
by UncleDaddy_XD_LOL December 30, 2020
When you have to sign off on something but the recipient actually needs to hear 'suck a bag of dick' or 'Go fuck yourself'
Dear Cst,

I'm so sorry that when you were so busy getting high on yourself and showing your powerful ability to have a complete lack of regard for human life, you bumped yourself on my elbow while you were throwing me around. In the future, instead of assaulting you with the sheer fact that my body even exists, I will hide in the bushes and try not to breath instead of asking for help.


by Iplantree June 26, 2020
A person who has a steady, reasonably-paid job that involves upholding standards who is happy to add their signature to any wrong or unethical thing that their employer asks them to sign off. Some examples might be a careless employees working as an Environmental Officer in a local government authority, a Social Worker in an under-staffed Department of Community Services or a Safety Officer at a mine site.
The last person in this position was just a sign-off monkey so for the first couple of months I was mostly sorting out problems.
by JiyaRe December 30, 2020