Where does “ຄັບ” come from?

ຄັບ (Lao) comes from Proto-Tai ɡapᴰ, from Middle Chinese 狹.

ຄັບ (Lao): narrow

Definitions

Step	Language	Word	Meaning
1	Proto-Tai	ɡapᴰ	close; tight; narrow
2	Middle Chinese	狹	—

ຄັບ — Etymology, Origin & Word History | Etymology Explorer