Ideogrammic compound (會意): 甶 (“spirit (abbreviated as 田)”) + 爪 (“claws, lower portion of 虎, tiger”) – a spirit/demon in shock/fear because of the claws (of a tiger).
From the Shuowen: “从甶，虎省。鬼頭而虎爪，可畏也。𤰲，古文省。” (“From 甶 and abridged 虎 [written as such in the Lesser Seal Script]. The head of a ghost encountering and frightened by the claws of a tiger. In the older script, [picture not shown, written with 甶 on top and 爪 below.]”)
胃 has an identical pronunciation and also features 田 on the top, but isn't related accord to the Shuowen, although it's used as the fǎnqiè of 畏.