chew, eat, munch
噍 centers on the physical act of chewing or munching food, with a focus on the mouth's repetitive motion. The broader sense of eating is a natural extension of this action.
噍 combines 口 (mouth) with 焦, which likely contributes the sound and may relate to the idea of something being consumed or processed. The exact historical development is uncertain.
The mouth 口 on the left is busy with the right side 焦, which looks like a bird (隹) over fire (灬). Imagine a bird roasting over a fire, and your mouth is chewing the cooked meat.
For ショウ, picture a chef saying 'show' as he demonstrates how to chew the roasted bird: show -> ショウ, and your mouth follows along.