The Proto-Indo-European root *kʷrep- "body, form, appearance" became Latin corpus "body". This was borrowed into Old Irish as corp, which combined with lū "small" (from PIE *legʷh-) to form luchorpán. This became modern Irish Gaelic lupracán and was borrowed into English as leprechaun.
In Germanic, *kʷrep- became *hrefiz-, becoming Old English hrif "belly" (according to the AHD, Oxford says "of obscure origin"). This combined with mid to form midriff.