A subgenre of rock music featuring heavy bass, trip-hop drum grooves, psychedelic guitars, SLOW tempos and ominous/mysterious lyrical themes. Can also use piano and experimental production to evoke a sophisticated "secret agent" vibe, or a mysterious far-away "underwater" feeling (hence the term murk).
Essentially, goth + grunge with electronic elements.
David Bowie's "Something in the Air (American Psycho Remix" is murk rock.
Rik Schaffer's instrumental tracks for VtM:B are murk rock.
Frøst's "Drag You Under" is murk rock.