SEMIDIURNAL Antonyms There are 9 antonyms of the word semidiurnal. (opposite meanings)Did you mean?Definition of SEMIDIURNALBest Opposite Words For SEMIDIURNALTop 20Top 10 Top 20 (Default)Top 50 Top 100 All All (Default)WordsPhrases All All (Default)Verb Noun Adjective Adverb RankWordSave?Synonyms..UsageType1annualadjectiveadj2constantnoun, adjectiven, adj3diurnaladjectiveadj4irregularadjectiveadj5monthlyadjectiveadj6nocturnaladjectiveadj7permanentadjectiveadj8sporadicadjectiveadj9weeklyadverb, adjectiveadv, adj Alternatives for ANNUAL Words (5)yearlyyearlongannualizedone-yearyearbookOpposite words for annual Alternatives for CONSTANT Words (28)unvaryingincessantinvariantperpetualconsistentcontinualenduringfixedimmovableimmutableongoingpersistentpredictableregularresolutestablesteadyunchangingundeviatinguniformunwaveringceaselesschangelessinvariablenever-endingunceasingunremittingunalteringPhrases (1)constant quantityOpposite words for constant Alternatives for DIURNAL Words (1)circadianOpposite words for diurnal Alternatives for IRREGULAR Words (28)atypicalaberrantanomalousdevianteccentricidiosyncraticnonconformingoddoutlandishpeculiaruncommonunconventionalunusualwaywardabnormalcoarseguerillaguerrillainsurgentmavericksecondsingulartemporaryunorthodoxunpredictableunstableunsteadyheterocliteOpposite words for irregular Alternatives for MONTHLY Words (15)constantcontinuouscyclicaldailyeverydayincessantperiodicrecurrentregularrepeatedroutinesteadysuccessiveweeklyyearlyOpposite words for monthly Alternatives for PERMANENT Words (19)lastingunendingabidingconsistentconstantenduringfirmfixedimmovableimmutableirreversibleperpetualstablesteadfastunalterableunchangingdurableeverlastingpermPhrases (1)permanent waveOpposite words for permanent Alternatives for SPORADIC Words (11)episodicfitfulhaphazardinfrequentintermittentirregularisolatedoccasionalrarescatteredspasmodicOpposite words for sporadic