clogged nose
鼽 centers on nasal blockage: a clogged or stuffy nose, often from congestion.
鼽 combines 鼻 (nose) with 九, which likely contributes the sound. The character expresses the idea of a blocked nose.
The nose 鼻 is blocked by something shaped like 九, like a bent plug, causing a clogged nose.
For グ, imagine a gooey substance clogging the nose: goo -> グ, and the nose is all stuffed up.