Source : Webster's Revised Unabridged Dictionary (1913)

Cutworm \Cut"worm`\ (-w?rm`), n. (Zo["o]l.)
   A caterpillar which at night eats off young plants of
   cabbage, corn, etc., usually at the ground. Some kinds ascend
   fruit trees and eat off the flower buds. During the day, they
   conceal themselves in the earth. The common cutworms are the
   larv[ae] of various species of {Agrotis} and related genera
   of noctuid moths.

Source : WordNet®

cutworm
     n : North American moth whose larvae feed on young plant stems
         cutting them off at the ground