Answer:

thunk

Answer	Crossword Clue
THUNK	Heavy landing sound
THUNK	Ideated, to Li'l Abner
THUNK	Thought wrong?

THUNK	"Who'da ... it?!"
THUNK	Ideated, nonstandardly
THUNK	Verb sung by the Scarecrow
THUNK	Heavy, muffled sound
THUNK	Dull sound
THUNK	Conceived in a nonstandard way