chump · noun, verb1
Origin uncertain; probably a blend of chunk and lump or stump, or perhaps a nasalised variant of chub (“someone chubby, something thick”). Compare Icelandic kubbur (“block of wood, chip (computing)”), Old Norse kumbr for kubbr (“block of wood”), English chop.
chump · verb2
Variant of chomp, itself a variant of champ (“to bite”). More at champ.
Etymology from Wiktionary, CC BY-SA 4.0.