1 definition by Janelle Thomas
(thu-with unvoiced "th", as in "thought"; precede by "super-" for added emphasis): an insult made unique by the fact that it is most often uttered in an extended whisper, and not audible by its target. A thu is any person who is engaging in an activity that makes onlookers roll their eyes, or that should be (but usually isn't) causing the perpetrator embarrassment. Similar in meaning but less pejorative than dumbass.
(A man is juggling loose oranges at the grocery store, dropping one occasionally, picking it up, and resuming.)
Passer-by, under his breath: "Thuuuuuuuu"
Passer-by, under his breath: "Thuuuuuuuu"
by Janelle Thomas April 14, 2008