A genre of 'indie' rock where the musicians and singer sound like they're drugged, and draped over a couch while playing, giving off the vibe that they're just on the verge of a nap and can't be bothered to write more interesting music. Music made by people that would rather be napping, to be listened to people that wish to nap. It's the kind of music that makes people with actual standards want to die.
Person 1: Hey, have you heard this song by Avi Buffalo
Person 2: You mean that sleepy napcore bullshit devoid of inspiration, energy and talent?
Person 1: That's the one!
Person 2: Yeah. I've heard it *yawn*