I don't think being a dirty SOB is it either. For me it's players that never shy away from contact on offense, backcheck and don't do flyby stick checks--they generally win contested situations IF they cannot outskate the opposition regularly (like Bratt...but he also was fine with the occasional body check). Brayden Point is a hard player in my opinion. The Tkachuks, Bennets, Ekblads, Nelsons, Pietrangelo, JT Millers...I just don't know who that is on the Devils. It was McRapey.
On defense they either win the puck with great effort in the corners, stand up to forechecks (mentally and physically) or, like Trouba, put the forward on his ass on a given play if they lack the footspeed. They don't get walked. They don't let a pass to a wide open player in the slot happen. They are not part of shift where they are hemmed in for two minutes.