motiveless

About 0.05 uses per million words.

Meaning

1. adjective Without a motive.

   This seems to have been a motiveless crime: no money was stolen, and nobody had cause to hate the victim.

Similar words

unmotivated unprovoked wanton malignity unmotived purposeless driveless motivationless mottoless incentiveless

Often followed by

malignity and murder crime murders malignancy resistance crimes action