From the Dryden translation of Plutarch's life of Pompey Magnus:

Gabinius, one of Pompey's friends, preferred a law, whereby there was granted to him, not only the government of the seas as admiral, but in direct words, sole and irresponsible sovereignty over all men. For the decree gave him absolute power and authority in all the seas within the pillars of Hercules, and in the adjacent mainland for the space of four hundred furlongs from the sea.

http://ancienthistory.about.com/library/bl/bl_text_plutarch_pompey.htm

From context it is obvious that irresponsible meant something different in Dryden's day -- the idea being that Pompey was not responsible to anyone, he didn't have to report back to a boss. The question is, how would you express that concept in a single word these days now that irresponsible has taken on a different meaning?

Bingley

Bingley