The Austronesian Comparative Dictionary

*hupak split, peel off

PWMP hupak split, peel off

WMP
Ibaloy opak the layers (compact leaves) that comprise the trunk (stem) of the banana tree; also outer leaves of such as cabbage or lettuce
Cebuano hupák develop a crack such that the separated pieces are no longer in contact
Maranao opak split, break
Mansaka opak strips peeled off trunk of an abaca or banana tree
Tiruray ʔufak split lengthwise by driving a blade along the grain
Malagasy ófaka scaling off, peeling off, as blistered skin