Where does “lỗi thời” come from?

lỗi thời (Vietnamese) comes from Vietnamese thối, from Proto-Chamic *ʔadhɛ̃y, from Proto-Malayo-Polynesian daqih, from Proto-Austronesian daqiS — forehead.

lỗi thời (Vietnamese): out-of-date; outdated; obsolete; obsolescent

Definitions

  1. out-of-date; outdated; obsolete; obsolescent

Ancestry of “lỗi thời”, step by step

lỗi thời traces back through two separate lines of ancestry.

via Vietnamese thối

StepLanguageWordMeaning
1Vietnamesethốirotten; fetid, putrid, stinking, foul-smelling;...
2Proto-Chamic*ʔadhɛ̃yforehead
3Proto-Malayo-Polynesiandaqihforehead
4Proto-AustronesiandaqiSforehead

via Vietnamese lỗi

StepLanguageWordMeaning
1Vietnameselỗimistake, fault, error
Every word from Proto-Austronesian daqiS →Every word from Proto-Malayo-Polynesian daqih →Every word from Proto-Chamic *ʔadhɛ̃y →