Where does “ความกินใจ” come from?

ความกินใจ (Thai) comes from Thai กินใจ, from Thai ใจ, from Proto-Tai cɤɰᴬ — heart; breath.

Ancestry of “ความกินใจ”, step by step

ความกินใจ traces back through two separate lines of ancestry.

via Thai กินใจ

StepLanguageWordMeaning
1Thaiกินใจto affect emotionally: to impress, to touch, to...
2Thaiใจheart; mind; spirit; breath
3Proto-Taicɤɰᴬheart; breath

via Thai ความ

StepLanguageWordMeaning
1Thaiความaffair; matter; content; essence; subject;...
2Proto-Taiɣwaːmᴬmatter
Every word from Proto-Tai cɤɰᴬ →Every word from Thai ใจ →Every word from Thai กินใจ →
ความกินใจ — Etymology, Origin & Word History | Etymology Explorer