Where does “ăn xổi ở thì” come from?

ăn xổi ở thì (Vietnamese) comes from Vietnamese thì, from Chinese 時, from Old Chinese 之.

Ancestry of “ăn xổi ở thì”, step by step

ăn xổi ở thì traces back through two separate lines of ancestry.

Step	Language	Word	Meaning
1	Vietnamese	thì	Dated form of thời; the prime time in terms of...
2	Chinese	時	—
3	Old Chinese	之	—

Step	Language	Word	Meaning
1	Vietnamese	ở	at, in; to be, to live, to stay, to remain
2	Proto-Vietic	ʔəh	to stay