Meaning of "subsob"

subsob •

v.
• • sumubsob (-um-) to fall on the face. Sumubsob siya sa pagmamadali. He fell on his face when he was rushing. magsubsob, isubsob (mag-:i-)

v.
• • to get intensely involved. Isubsob mo ang sarili mo sa iyong ginagawa. Involve yourself intensely in what you're doing.