grub

n. 1 larva of an insect. 2 colloq. Food. v. (-bb-) 1 dig superficially. 2 (foll. By up, out) a extract by digging. B extract (information etc.) By searching in books etc. 3 rummage. [old english]

v. i. To dig in or under the ground, generally for an object that is difficult to reach or extricate; to be occupied in digging.