adj.不规律的，偶尔的
Merriam-Webster Online Dictionary
sporadic (adjective)occurring occasionally, singly, or in irregular or instances - random sporadic protests a sporadic disease infrequent
Merriam-Webster Online Thesaurus
sporadic (adjective)1.
lacking in steadiness or regularity of occurrence
SYNONYMS:
aperiodic, casual, catchy, choppy, discontinuous, episodic ( episodical), erratic, intermittent, irregular, occasional, spasmodic, spastic, sporadic, spotty, unsteadyRELATED WORDS:
convulsive, sudden, violent; broken, disconnected, fragmentary, interrupted; aimless, arbitrary, desultory, haphazard, hit-and-miss, hit-or-miss, odd, random, scattered, slapdash, stray; capricious, changeful, changing, flickery, fluctuating, fluid, inconstant, mercurial, mutable, temperamental, uncertain, unpredictable, unsettled, unstable, varying, wavering; changeable, fickle, variable, volatileNEAR ANTONYMS:
changeless, equable, even, stable, stationary, uniform; unchanging, unvarying, unwavering; methodical ( methodic), orderly, systematic; unrelenting, unremitting2.
not often occurring or repeated
SYNONYMS:
isolated, occasional, odd, rare, sporadicRELATED WORDS:
scarce, scattered, uncommon, unique, unusual; choppy, discontinuous, erratic, fitful, intermittent, irregular, spasmodic, spotty, unsteadyNEAR ANTONYMS:
daily, regular; common, ordinary, routine