Definition of "ingrained"

But ever since the concept of "hamartia" recurred through Aristotle's Poetics, in an attempt to describe man's ingrained iniquity, our impulse has been to identify a telling defect in those brought suddenly and dramatically low.

2014 October 21, Oliver Brown, “Oscar Pistorius jailed for five years – sport afforded no protection against his tragic fallibilities: Bladerunner's punishment for killing Reeva Steenkamp is but a frippery when set against the burden that her bereft parents, June and Barry, must carry ”, in The Daily Telegraph (Sport)‎