1.  abruptness(n = noun.attribute) brusqueness, curtness, gruffness, shortness - an abrupt discourteous manner;
is a kind of discourtesy, rudeness
Derived form adjective abrupt₄

2.  abruptness(n = noun.attribute) precipitousness, steepness - the property possessed by a slope that is very steep;
is a kind of gradient, slope
Antonym: gradualness
Derived form adjective abrupt₃

3.  abruptness(n = noun.attribute) precipitance, precipitancy, precipitateness, precipitousness, suddenness - the quality of happening with headlong haste or without warning;
is a kind of haste, hastiness, hurriedness, hurry, precipitation
Derived form adjective abrupt₂

1.  The state of being abrupt or broken; craggedness; ruggedness; steepness. [1913 Webster]

2.  Suddenness; unceremonious haste or vehemence; as, abruptness of style or manner. [1913 Webster]

N  instantaneity, instantaneousness, immediacy, suddenness, abruptness, moment, instant, second, minute, twinkling, trice, flash, breath, crack, jiffy, coup, burst, flash of lightning, stroke of time, epoch, time, time of day, time of night, hour, minute, very minute, very time, very hour, present time, right time, true time, exact correct time, instantaneous, momentary, sudden, immediate, instant, abrupt, discontinuous, precipitous, precipitant, precipitate, subitaneous, hasty, quick as thought, quick as lightning, quick as a flash, rapid as electricity, speedy, quick, fast, fleet, swift, lively, blitz, rapid (velocity), instantaneously, in no time, in less than no time, presto, subito, instanter, suddenly, at a stroke, like a shot, in a moment, in the blink of an eye, in the twinkling of an eye, in a trice, in one's tracks, right away, toute a l'heure, at one jump, in the same breath, per saltum, uno saltu, at once, all at once, plump, slap, at one fell swoop, at the same instant, immediately, extempore, on the moment, on the spot, on the spur of the moment, no sooner said than done, just then, slap-dash, touch and go, no sooner said than done.