move
吪 is a rare kanji whose standalone meaning is unclear. The given gloss "move" suggests a connection to motion or change, but without more context its precise sense is uncertain.
The exact historical development of 吪 is uncertain. It combines 口 (mouth) with 化 (change), but whether this is a phono-semantic compound or a later formation is unclear.
A mouth 口 that changes 化 could suggest movement or transformation through speech, but the connection is speculative.
For グウ, imagine a mouth making a goo sound as it moves: goo -> グウ, and the mouth shifts shape.