whoops[hwo̵ops, wo̵ops; hwo̵̅o̅ps, wo̵̅o̅ps]
whoops 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.
used to express sudden or surprised dismay, or, sometimes, implied apology, after one has blundered, tripped, broken something, misspoken, etc.
whoops definition by American Heritage Dictionary
Used to express apology or mild surprise.