Where does “無來由” come from?

無來由 (Chinese) comes from Malay Melayu, from Malay Malayu, from Old Javanese layū, from Proto-Sunda-Sulawesi lariw, from Proto-Malayo-Polynesian laʀiw, from Proto-Austronesian laʀiw.

Ancestry of “無來由”, step by step

Step	Language	Word	Meaning
1	Malay	Melayu	Malay
2	Malay	Malayu	—
3	Old Javanese	layū	to run
4	Proto-Sunda-Sulawesi	lariw	—
5	Proto-Malayo-Polynesian	laʀiw	—
6	Proto-Austronesian	laʀiw	—

Every word from Proto-Austronesian laʀiw →Every word from Proto-Malayo-Polynesian laʀiw →Every word from Proto-Sunda-Sulawesi lariw →