Synonyms and related words :
at irregular intervals, at random, brokenly, by catches, by fits, by jerks, by snatches, capriciously, desultorily, disconnectedly, discontinuously, eccentrically, erratically, fitfully, flutteringly, haltingly, in snatches, in spots, inconstantly, intermittently, irregularly, lurchingly, nonuniformly, off and on, patchily, quakingly, quaveringly, quiveringly, roughly, saltatorily, shakily, shudderingly, spasmodically, sporadically, spottily, tremblingly, tremulously, uncertainly, unevenly, unmethodically, unpredictably, unrhythmically, unsteadily, unsystematically, variably, waveringly, whimsically, wobblingly