Where does “ปัญญาอ่อน” come from?

ปัญญาอ่อน (Thai) comes from Thai ปัญญา, from Pali paññā, from Sanskrit प्रज्ञा, from Sanskrit ज्ञा, from Proto-Indo-Aryan ȷ́naH-, from Proto-Indo-Iranian ǰnaH-, from Proto-Indo-European ǵneh₃- — to know.

ปัญญาอ่อน (Thai): intellectually disabled; idiotic; stupid;...

Definitions

intellectually disabled; idiotic; stupid;...

Ancestry of “ปัญญาอ่อน”, step by step

ปัญญาอ่อน traces back through two separate lines of ancestry.

via Thai ปัญญา

Step	Language	Word	Meaning
1	Thai	ปัญญา	wisdom; knowledge; intelligence
2	Pali	paññā	wisdom; insight, understanding
3	Sanskrit	प्रज्ञा	feminine singular nominative of प्रज्ञ; wisdom,...
4	Sanskrit	ज्ञा	to know
5	Proto-Indo-Aryan	ȷ́naH-	—
6	Proto-Indo-Iranian	ǰnaH-	—
7	Proto-Indo-European	ǵneh₃-	to know

via Thai อ่อน

Step	Language	Word	Meaning
1	Thai	อ่อน	young; soft
2	Proto-Southwestern Tai	*ʔɔːnᴮ¹	—
3	Proto-Tai	ʔwuːnᴮ	young; soft; young, soft

Every word from Proto-Indo-European ǵneh₃- →Every word from Proto-Indo-Iranian ǰnaH- →Every word from Proto-Indo-Aryan ȷ́naH- →