tarnation definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
damnation: also used as an intensifier: what in tarnation is that?
Origin: probably ; from 'tarnal (short dialect, dialectal form of eternal) plush (dam)nation
tarnation definition by American Heritage Dictionary
New England & Southern U.S.noun
The act of damning or the condition of being damned.interjection
Used to express anger or annoyance.
Origin: tarn(al) + (damn)ation.Regional Note: The noun and interjection tarnation illustrate suffixation, the addition of a suffix to a word. Tarnation and darnation (the latter probably having come first) are both euphemistic forms of damnation. Tarnation seems to have been influenced by tarnal, another mild oath derived from (e)ternal! The Oxford English Dictionary cites late-18th-century examples of tarnation from New England, indicating that it has been part of American speech since colonial days.