The "
past tense" of
think.
"I just got an idea!" "way to go, Boris!" "<proudly>I thunk it up myself.</proudly>".
This is not proper spelling, but is instead hackish (or one could argue, childish) as it an overgeneralization of other similarly-spelled words. The thinkology is as follows:
"Sink" → "sank" → "sunk" (correct english)
"drink" → "drank" (correct up to this point) → "drunk" (incorrect, but often done for humorous value)
Therefore: "think" → "thank" → "thunk".
"Thank" is not used (nearly as often as "thunk" is,)? as it's already a real word (and unlike "drunk" offers little/no humour value).