wacko

Etymology
From.

Adjective

 * 1)  Amusingly eccentric or irrational.

Translations

 * German:, ,
 * Russian:

Noun

 * 1)  An amusingly eccentric or irrational person.

Interjection

 * 1)  hurrah!

Etymology
Probably related to

Noun

 * 1) rock, boulder