Webster's Revised Unabridged Dictionary · 1913

Cur

Cur (kûr) , noun

[Old English curre, kur; compare dial. Swedish kurre dog, OD. korre watchdog, and Icelandic kurra to murmur, grumble, Swedish kurra to rumble, croak, Danish kurre to coo, whirr; prob. of imitative origin.]

1.
A mongrel or inferior dog.
They... like to village curs, Bark when their fellows do. — Shakespeare
2.
A worthless, snarling fellow; -- used in contempt.
What would you have, you curs, That like nor peace nor war? — Shakespeare