Where does “boş laf” come from?

boş laf (Turkish) comes from Turkish boş, from Ottoman Turkish بوش, from Proto-Turkic boĺ — free; empty.

Ancestry of “boş laf”, step by step

boş laf traces back through two separate lines of ancestry.

via Turkish boş

StepLanguageWordMeaning
1Turkishboşempty, unoccupied, free
2Ottoman Turkishبوشempty, unoccupied, free, vacant
3Proto-Turkicboĺfree; empty

via Turkish laf

StepLanguageWordMeaning
1Turkishlafword, speech (something said)
2Persianلافboast; bluff
Every word from Proto-Turkic boĺ →Every word from Ottoman Turkish بوش →Every word from Turkish boş →
boş laf — Etymology, Origin & Word History | Etymology Explorer