Disoriented or Disorientated

Disoriented' has been in use in British English since the 1600s, whilst 'disorientated' is recorded nowhere prior to the 1950s. However, both now seem to be treated as options in common usage.

The word originates from the word Orient meaning "East" and the original word Oriented meant to be facing East. It is thought the word derived from nautical use where to be off course meant you were not heading East and thus "Disoriented"