John, Thump is firmness. Thump readings come off the thump meter, which was developed for supers to quantify how firm it is out there. Not sure if it ever gets used.
Judge, you highlight how much terminology matters. Collarless, to me, means the rough is immediately adjacent to the green. Fairway height cut green surrounds are the collar. There might only be a foot or three between the two on the stimp, but if the grass immediately adjacent to the putting green is too long, the ball stopping is assured, sooner, and therefore less exciting, less nuancy. It's that last 1/4 revolution of the ball, combine w/ firmness and slope, that determines the most sophisticated form of "rub o' green" on a properly melded course.