Ariyamaggasutta 2.2

2.2

Idha, bhikkhave, ekacco sabyābajjhaṃ kāyasaṅkhāraṃ abhisaṅkharoti …pe… idaṃ vuccati, bhikkhave, kammaṃ kaṇhaṃ kaṇhavipākaṃ.

It’s when someone makes hurtful choices by way of body, speech, and mind. These are called dark deeds with dark results.