THESAURUS
at intervals, at irregular intervals, at random, at regular intervals, at stated times, brokenly, by catches, by fits, by jerks, by skips, by snatches, capriciously, constantly, desultorily, disconnectedly, discontinuously, eccentrically, erratically, every so often, fitfully, haltingly, haphazardly, here and there, in snatches, in spots, inconstantly, infrequently, irregularly, jerkily, like clockwork, lurchingly, methodically, nonuniformly, occasionally, off and on, patchily, per saltum, punctually, randomly, regularly, roughly, skippingly, spasmodically, sporadically, spottily, steadily, systematically, uncertainly, unevenly, uniformly, unmethodically, unpredictably, unrhythmically, unsteadily, unsystematically, variably, whimsically, willy-nilly, wobblingly
