Derived from the sound food makes when falling from a row in a vending machine, "thunk" is a general term for food you buy when you have the munchies, but your funds are limited to small change only.
Imagine the sound made by a Honeybun when you buy it from a machine after smoking pot all night.
Dude, you're eating thunk.
Dude, let's go get some thunk.
Dude, you're eating thunk.
Dude, let's go get some thunk.
by Devlan July 27, 2006
Get the thunkmug. by Joel27 September 8, 2004
Get the thunkmug. Sound made from unzipping the pants and a large member hitting the floor. Normally used when someone makes you mad and you want to get them back or do something bad to them.
by Bob May 17, 2003
Get the Zip thunkmug. 
A sarcastic expression that explains that everybody/somebody has already thought of that or has acquired that information already
by forever.and.fucking.always March 17, 2015
Get the who'da thunkmug. by moonpie n widow ross January 7, 2012
Get the thunk-fuckedmug. n. A long awaited, brilliant idea or thought that can only be the result of God himself whacking it into your head.
The only possible explanation for planning this trip had to be a God-thunk, considering how absent minded she is.
by sneekersotoole December 20, 2009
Get the God-thunkmug.