a grub, or larva, that lives and develops in manure or mud
2.
a miser
muckworm in American English
(ˈmʌkˌwɜːrm)
noun
1. (not in technical use)
the larva of any of several insects, as the dung beetle, which lives in or beneath manure
2.
a miser
Word origin
[1590–1600; muck + worm]This word is first recorded in the period 1590–1600. Other words that entered Englishat around the same time include: class, jolt, operator, squeeze, tube