Insidious Definition & Meaning - Merriam-Webster

The meaning of INSIDIOUS is having a gradual and cumulative effect : subtle. How to use insidious in a sentence. insidious, sinister, or pernicious? Login SignUp Hello, Games&Quizzes Thesaurus WordoftheDay Features BuyingGuide M-WBooks JoinMWU MyWordsMyWords ViewRecents Account LogOut insidious adjective SaveWord in·​sid·​i·​ous |\in-ˈsi-dē-əs \ Definitionofinsidious 1a :havingagradualandcumulativeeffect:subtle theinsidiouspressuresofmodernlife b ofadisease :developingsograduallyastobewellestablishedbeforebecomingapparent 2a :awaitingachancetoentrap:treacherous b :harmfulbutenticing:seductive insidiousdrugs OtherWordsfrominsidious insidious,sinister,orpernicious? MoreExampleSentences LearnMoreAboutinsidious OtherWordsfrominsidious insidiously adverb insidiousness noun insidious,sinister,orpernicious? Fewwouldchoosetobeassociatedwithpeopleorthingsthatareinsidious,sinister,orpernicious;allthreeofthesewordshavedecidedlyunpleasantmeanings,eachwithitsownparticularshadeofnastiness. InsidiouscomesfromaLatinwordfor“ambush”(insidiae),whichisfitting,asthiswordoftencarriesthemeanings“deceitful,”“stealthy,”or“harmfulinanimperceptiblefashion.”Thefirsttwomeaningsmaybeappliedtopeopleorthings(“aninsidiousenemy,”“aninsidiousplot”),whilethelastisusuallyappliedtothings(“insidiousproblems,”“insidioussexism”),inparticulartothegradualprogressofadisease(“aninsidiousmalignancy”). SinistercomesfromaLatinwordmeaning“ontheleftside,unlucky,inauspicious.”Althoughitiscommonlyusedtodayinthesense“evil”(“asinistercultleader”;“asinisterplot”),itmayalsosuggestanominousforeshadowingofsomeunfavorableturnofevents(“asinisteromen”). Pernicioushaslargelystayedtruetoitsetymologicalroot,theLatinnounpernicies“ruin,destruction.”ItsoriginalmeaninginEnglish,“highlyinjuriousordestructive,”usuallyappliestothings(“perniciousapathy,”“perniciouseffects”)andmedicalconditions(“perniciousfever,”“perniciousanemia”).Whenappliedtopeople,perniciousmeans“wicked.” ExamplesofinsidiousinaSentence Butthelitigationisalsopromptingasubtleandinsidiouschangeinthewaythatmedicineispracticed,whichaffectsanyonewhoconsultsahealthprofessional,eveniftheywouldnotdreamofsettingfootinalawyer'soffice.Itisknownas"defensivemedicine." —GeoffWatts,NewScientist,23–29Oct.2004 Spinissometimesdismissedasasimpleeuphemismforlying.Butit'sactuallysomethingmoreinsidious:indifferencetothetruth. —MichaelKinsley,Time,25Dec.2000–1Jan.2001 Astheseboatsagedandbeddingcompoundsdeteriorated,thewatertorturebegan,whichledtorot,corrosion,andotherinsidiousproblems. —RalphNaranjo,CruisingWorld,April1999 Mostpeoplewiththisinsidiousdiseasehavenoideathattheyareinfected. RecentExamplesontheWeb Moreinsidiousistherateofpolicestopsandevenlethalshootingsandallegationsofmarijuanapossession. — MayaWiley,TheNewRepublic,8July2022 Theinsidiousthingaboutharassmentisthatitisoftenpreemptedbyasetofbehaviorsthatmaygounseen,likemicroaggressions(i.e.,slights,barbs,demeaningcomments). — SarahRowell,Forbes,17May2022 Thatgetsatthemostinsidiousthingaboutthesite’sdesign—sincetheextremismisdressedupinanofficialglossofbadgesandthedigitaltrinketsofstatus. — LosAngelesTimes,25Nov.2020 Theticksthatcarrythisinsidiousdiseaseareeverywhere. — BostonGlobe.com,3June2022 Thisconqueringnewstyleofreasoning,Bermanargues,wasinsidious. — IdreesKahloon,TheNewYorker,16May2022 WhereassomeadversarialattacksseektodisruptorconfoundtheAI,anotherequallyifnotmoreinsidiousformofdeceptioninvolvesgettingtheAItoactonthebehalfoftheattacker. — LanceEliot,Forbes,16May2022 Sinisfarmoreinsidiousthanmostwanttoimagine,andthecostsoftheologicalfailurearehorrifying. — R.AlbertMohler,WSJ,26May2022 Inthissense,statelawscouldbeevenmoreinsidiousthanthePolishlaw,whichdoesnotexplicitlyencouragevigilantism. — AnnaLouieSussman,TheNewYorker,17May2022 SeeMore Theseexamplesentencesareselectedautomaticallyfromvariousonlinenewssourcestoreflectcurrentusageoftheword'insidious.'ViewsexpressedintheexamplesdonotrepresenttheopinionofMerriam-Websteroritseditors.Sendusfeedback. FirstKnownUseofinsidious 1545,inthemeaningdefinedatsense2a HistoryandEtymologyforinsidious Latininsidiosus,frominsidiaeambush,frominsidēretositin,siton,fromin-+sedēretosit—moreatsit LearnMoreAboutinsidious Shareinsidious PosttheDefinitionofinsidioustoFacebook SharetheDefinitionofinsidiousonTwitter TimeTravelerforinsidious Thefirstknownuseofinsidiouswas in1545 Seemorewordsfromthesameyear FromtheEditorsatMerriam-Webster WordsoftheYear:ADecadeinReview WordsoftheYear:ADecadeinReview Let’stakealookatadecadeinwords. Trending:Sondland:UkraineEffort... Trending:Sondland:UkraineEffort'Insidious' RedCarpetWords:OurTop7... RedCarpetWords:OurTop7Movie-RelatedWordTrends Getreadyforyourclose-up,'revenant' DictionaryEntriesNearinsidious insidiate insidious insight SeeMoreNearbyEntries  Statisticsforinsidious LastUpdated 17Jul2022 Look-upPopularity CitethisEntry “Insidious.”Merriam-Webster.comDictionary,Merriam-Webster,https://www.merriam-webster.com/dictionary/insidious.Accessed26Jul.2022. Style:MLA MLA Chicago APA Merriam-Webster MoreDefinitionsforinsidious insidious adjective in·​sid·​i·​ous |\in-ˈsid-ē-əs \ Medical Definitionofinsidious :developingsograduallyastobewellestablishedbeforebecomingapparent aninsidiousdisease OtherWordsfrominsidious insidiously adverb MorefromMerriam-Websteroninsidious Thesaurus:Allsynonymsandantonymsforinsidious Nglish:TranslationofinsidiousforSpanishSpeakers BritannicaEnglish:TranslationofinsidiousforArabicSpeakers WORDOFTHEDAY Luddite SeeDefinitionsandExamples» GetWordoftheDaydailyemail! TestYourVocabulary OddHabitsandQuirks Whichofthefollowingbestdescribesaneasilyirritatedperson? superficial tetchy flashy gregarious Canyouspellthese10commonlymisspelledwords? TAKETHEQUIZ Adailychallengeforcrosswordfanatics. TAKETHEQUIZ SubscribetoAmerica'slargestdictionaryandgetthousandsmoredefinitionsandadvancedsearch—adfree! 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