Meaning One: Fantastic, Amazing, Startlingly Impressive.

Meaning Two: Disappointing, Unpleasant, Overdone.

Meaning Three: A testimony made by a clam.

Word Origins:
Originally it was verbal only, pronounced unexpectedly by a text to speech program.
Eventually out of necessity it was given a non verbal spelling and since then it's popularity has risen considerably from a buzz word to an intricate part of everyday language.
While at first some were confused as to it's nature (being inherently contradictory) it's meaning is more often than not determined by context, and failing that, attributed to sarcasm.
"I bought A game yesterday, it was clamstimony!"

"Wow. Today has been such a clamstimony day."
by Not a Cobra March 18, 2010
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Clamstimony (Adj): Used to describe how illogical something is.
Sir, your theory is clamstimony.
by ASwarmofAngryBees March 18, 2010
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