Sporadic: will always trigger the reaction "Sporadic E," which is a type of "skip," experienced in radio communication. The link will provide more information for the curious. The reaction is testimony to my youthful exposure to Amateur Radio. It is a useful adjective, and sporadically a fine adverb.
Sporadic Spo*rad"ic (-r[a^]d"[i^]k), a. [Gr. ? scattered, fr. ?, ?, scattered, fr. ? to sow seed, to scatter like seed: cf. F. sporadique. See Spore.] Occurring singly, or apart from other things of the same kind, or in scattered instances; separate; single; as, a sporadic fireball; a sporadic case of disease; a sporadic example of a flower.
Sporadic disease a disease which occurs in single and scattered cases. See the Note under Endemic, a.
-- From The Collaborative International Dictionary of English v.0.48
adj : recurring in scattered and irregular or unpredictable
instances; "a city subjected to sporadic bombing raids"
-- From WordNet (r) 2.0
165 Moby Thesaurus words for "sporadic":
aimless, amorphous, broadcast, broken, capricious, careening, casual, catching, catchy, chance, changeable, changing, choppy, communicable, contagious, desultory, deviating, deviative, deviatory, different, diffuse, disarticulated, disconnected, discontinuous, discrete, disjunct, disordered, disorderly,
dispersed, dispread, disproportionate, disseminated, dissipated, distributed, divaricate, divergent, diversified, diversiform, eccentric, endemic, epidemial, epidemic, epiphytotic, epizootic, erose, erratic, few, fitful, flickering, fluctuating, formless, frivolous, gratuitous, guttering, halting, haphazard, herky-jerky,
heteroclite, hit-or-miss, immethodical, impulsive, inchoate, incoherent, inconsistent, inconstant, indiscriminate, infectious, infective, inoculable, intermittent,
intermitting, irregular, jagged, jerky, lurching, meaningless, mercurial, misshapen, motley, mutable, nonconformist, nonstandard, nonsymmetrical, nonsystematic,
nonuniform, occasional, on-again-off-again, orderless, pandemic, patchy, periodical, pestiferous, pestilential, planless, pluralistic, promiscuous, ragged, rambling, random, rare, rough, scarce, scattered, scrappy, seldom, senseless, separate, shapeless, single, snatchy, sparse, spasmatic, spasmic, spasmodic,
spasmodical, spastic, spotty, spread, spreading, staggering, straggling, straggly, strewn, strown, systemless, taking, unarranged, uncertain, unclassified, uncommon, undirected, unequable, unequal, uneven, unexpected, unfrequent, ungraded,
unjoined, unmethodical, unmetrical, unordered, unorganized, unorthodox, unregular, unrhythmical, unsettled, unsorted, unstable, unsteady, unsymmetrical, unsystematic, ununiform, vague, variable, variegated, variform, various, varying, veering, wandering, wavering, widespread, wobbling, wobbly, zymotic
-- From Moby Thesaurus II by Grady Ward, 1.0