A message sent on an IM client while the other person is offline.
I sent my boss an offliner, I hope he gets it on time.
by Vicrum December 19, 2007
One who has yet to embrace the use of IM, microblogging, commenting, etc. as a means of communications and "social" relationship building.
My friend isn't on Twitter yet. Total offliner...
by juicecowboy August 19, 2009