| operetaoperettaNoun | Noun |
| operovatoperate; perform surgeryVerb | Verb |
| opicemonkeyNoun | Noun |
| opičkalittle monkeyNoun | Noun |
| opilýdrunkAdjective | Adjective |
| opozičníoppositionAdjective | Adjective |
| opravarepairNoun | Noun |
| opravářrepairmanNoun | Noun |
| opravdovýrealAdjective | Adjective |
| opravdureally, trulyAdverb | Adverb |
| opravitcorrect; fix; repairVerb | Verb |
| opravnarepair shopNoun | Noun |
| opravovatfix; repair; correctVerb | Verb |
| optikaoptician shopNoun | Noun |
| optimistaoptimistNoun | Noun |
| optimistickýoptimisticAdjective | Adjective |
| optimistkafemale optimistNoun | Noun |
| oranžovýorangeAdjective | Adjective |
| ordinacedoctor's officeNoun | Noun |
| ordinačníconsulting-room; office-hoursAdjective | Adjective |
| ordinovatsee patients; prescribeVerb | Verb |
| organizaceorganizationNoun | Noun |
| organizátororganizerNoun | Noun |
| organizovatorganizeVerb | Verb |
| orchestrorchestraNoun | Noun |
| orientaceorientationNoun | Noun |
| orientačníapproximate; orientationalAdjective | Adjective |
| origináloriginalNoun | Noun |
| originálníoriginalAdjective | Adjective |
| orlicefemale eagleNoun | Noun |
| oslavacelebrationNoun | Noun |
| oslavitcelebrateVerb | Verb |
| oslovovataddress; speak toVerb | Verb |
| osmeightNumber | Number |
| osmažitfry lightly; fryVerb | Verb |
| osmdesáteightyNumber | Number |
| osmnácteighteenNumber | Number |
| osmnáctýeighteenthNumber | Number |
| osobapersonNoun | Noun |
| osobněpersonally, in personAdverb | Adverb |
| osobnípersonalAdjective | Adjective |
| osobnostpersonalityNoun | Noun |
| osprchovat setake a showerVerb | Verb |
| ostatníotherAdjective | Adjective |
| ostrovislandNoun | Noun |
| ostrýsharp; spicyAdjective | Adjective |
| ostříhatcut hair; trimVerb | Verb |
| ostýchavýshyAdjective | Adjective |
| ošetřittreat; attend toVerb | Verb |
| ošetřovatcare for; treatVerb | Verb |
| ošetřovatelmale caregiverNoun | Noun |
| ošetřovatelkafemale caregiverNoun | Noun |
| ošetřovnécare allowanceNoun | Noun |
| ošklivýuglyAdjective | Adjective |
| otáčet seturn aroundVerb | Verb |
| otáčivýrevolvingAdjective | Adjective |
| otázkaquestionNoun | Noun |
| otecfatherNoun | Noun |
| oteklýswollenAdjective | Adjective |
| otevíracíopeningAdjective | Adjective |
| otevíratopenVerb | Verb |
| otevřenoopenAdverb | Adverb |
| otevřenostopennessNoun | Noun |
| otevřítopenVerb | Verb |
| otočit seturn aroundVerb | Verb |
| otrávitpoisonVerb | Verb |
| otvíracíopeningAdjective | Adjective |
| otvíratopenVerb | Verb |
| ověřenýverified; confirmedAdjective | Adjective |
| ověřitverifyVerb | Verb |
| ověřovatverify; certifyVerb | Verb |
| ovocefruitNoun | Noun |
| ovocnýfruityAdjective | Adjective |
| ozdobaornamentNoun | Noun |
| označitmark; labelVerb | Verb |
| oznámenínoticeNoun | Noun |
| oženit seget married (man)Verb | Verb |
| pacientpatientNoun | Noun |
| padatfallVerb | Verb |
| padesátfiftyNumber | Number |
| padesátýfiftiethNumber | Number |
| páchnoutstinkVerb | Verb |
| pakthen, after thatAdverb | Adverb |
| palačinkapancakeNoun | Noun |
| paličatýstubbornAdjective | Adjective |
| pálivýspicy; hotAdjective | Adjective |
| památkamonumentNoun | Noun |
| památkysightsNoun | Noun |
| pamatovat sirememberVerb | Verb |
| panMr.; sirNoun | Noun |
| pángentlemanNoun | Noun |
| panamskýPanamanian; Panama-relatedAdjective | Adjective |
| panelpanelNoun | Noun |
| panelákprefab apartment blockNoun | Noun |
| panenkadollNoun | Noun |
| pánevpanNoun | Noun |
| paníMrs.; ladyNoun | Noun |
| panoramapanorama; wide viewNoun | Noun |
| pantofleslipper; slippersNoun | Noun |
| papírpaperNoun | Noun |