Easton's 1897 Bible Dictionary:

Asnapper
   probably the same as Assur-bani-pal (Sardanapalos of the
   Greeks), styled the "great and noble" (Ezra 4:10), was the son
   and successor (B.C. 668) of Esar-haddon (q.v.). He was
   "luxurious, ambitious, and cruel, but a magnificent patron of
   literature." He formed at Nineveh a library of clay tablets,
   numbering about 10,000. These are now mostly in the British
   Museum. They throw much light on the history and antiquities of
   Assyria.

     Assur-bani-pal was a munificent patron of literature, and the
   conqueror of Elam. Towards the middle of his reign his empire
   was shaken by a great rebellion headed by his brother in
   Babylon. The rebellion was finally put down, but Egypt was lost,
   and the military power of Assyria was so exhausted that it could
   with difficulty resist the hordes of Kimmerians who poured over
   Western Asia. (See NINEVEH.)


Hitchcock's Bible Names Dictionary (late 1800's):

Asnapper, unhappiness; increase of danger