Where does “cứng rắn” come from?

cứng rắn (Vietnamese) comes from Vietnamese rắn, from Proto-Vietic m-rəɲʔ, from Proto-Mon-Khmer (d)mrəɲʔ — body louse.

cứng rắn (Vietnamese): strict; tough; harsh; severe

Definitions

  1. strict; tough; harsh; severe

Ancestry of “cứng rắn”, step by step

cứng rắn traces back through two separate lines of ancestry.

via Vietnamese rắn

StepLanguageWordMeaning
1Vietnameserắna non-constricting snake, as opposed to a trăn;...
2Proto-Vieticm-rəɲʔbody louse
3Proto-Mon-Khmer(d)mrəɲʔbody louse

via Vietnamese cùng

StepLanguageWordMeaning
1Vietnamesecùngthe end, limit; with; and
2Middle Chinese宮—
Every word from Proto-Mon-Khmer (d)mrəɲʔ →