| odpovědní listanswer sheetWortkombination | Wortkombination |
| odpovídatanswer; answer regularlyVerb | Verb |
| odskočit sileave for a momentPhrase | Phrase |
| odtáhnoutpull away; tow awayVerb | Verb |
| odtamtudfrom thereAdverb | Adverb |
| odtudfrom hereAdverb | Adverb |
| odvážnýbrave; boldAdjektiv | Adjektiv |
| odvéstlead away; take awayVerb | Verb |
| odvézttake away by vehicle; drive awayVerb | Verb |
| ohlásitreport; announce; registerVerb | Verb |
| ohňostrojfireworks displaySubstantiv | Substantiv |
| ohodnocenívaluationSubstantiv | Substantiv |
| oholit seshave oneselfVerb | Verb |
| ochotawillingnessSubstantiv | Substantiv |
| ochranaprotectionSubstantiv | Substantiv |
| ochutnattaste; try food or drinkVerb | Verb |
| ochutnávattaste; sample repeatedlyVerb | Verb |
| ojetýused; worn (esp. car)Adjektiv | Adjektiv |
| okamžitěimmediatelyAdverb | Adverb |
| oknowindowSubstantiv | Substantiv |
| okoeyeSubstantiv | Substantiv |
| okolísurroundingsSubstantiv | Substantiv |
| okopírovatcopyVerb | Verb |
| okresnídistrictAdjektiv | Adjektiv |
| okupaceoccupationSubstantiv | Substantiv |
| okurkacucumberSubstantiv | Substantiv |
| okurkovýcucumberAdjektiv | Adjektiv |
| olejoilSubstantiv | Substantiv |
| olovoleadSubstantiv | Substantiv |
| olympiádaOlympicsSubstantiv | Substantiv |
| omáčkasauceSubstantiv | Substantiv |
| omezené ručenílimited liabilityWortkombination | Wortkombination |
| omezenýlimited; restrictedAdjektiv | Adjektiv |
| omlouvám seI'm sorry; excuse mePhrase | Phrase |
| omlouvat seapologise; apologizeVerb | Verb |
| omluvit seapologiseVerb | Verb |
| omylmistakeSubstantiv | Substantiv |
| onhePronomen | Pronomen |
| onashePronomen | Pronomen |
| opačnýoppositeAdjektiv | Adjektiv |
| opakovatrepeatVerb | Verb |
| opalovánítanningSubstantiv | Substantiv |
| opalovat sesuntanVerb | Verb |
| operaoperaSubstantiv | Substantiv |
| operaceoperationSubstantiv | Substantiv |
| operetaoperettaSubstantiv | Substantiv |
| operovatoperate; perform surgeryVerb | Verb |
| opicemonkeySubstantiv | Substantiv |
| opičkalittle monkeySubstantiv | Substantiv |
| opilýdrunkAdjektiv | Adjektiv |
| opozičníoppositionAdjektiv | Adjektiv |
| opravarepairSubstantiv | Substantiv |
| opravářrepairmanSubstantiv | Substantiv |
| opravdovýrealAdjektiv | Adjektiv |
| opravdureally, trulyAdverb | Adverb |
| opravitcorrect; fix; repairVerb | Verb |
| opravnarepair shopSubstantiv | Substantiv |
| opravna obuvishoe repair shopWortkombination | Wortkombination |
| opravna oděvůclothing repair shopWortkombination | Wortkombination |
| opravovatfix; repair; correctVerb | Verb |
| optikaoptician shopSubstantiv | Substantiv |
| optimistaoptimistSubstantiv | Substantiv |
| optimistickýoptimisticAdjektiv | Adjektiv |
| optimistkafemale optimistSubstantiv | Substantiv |
| oranžovýorangeAdjektiv | Adjektiv |
| ordinacedoctor's officeSubstantiv | Substantiv |
| ordinačníconsulting-room; office-hoursAdjektiv | Adjektiv |
| ordinační hodinydoctor's office hoursWortkombination | Wortkombination |
| ordinovatsee patients; prescribeVerb | Verb |
| organizaceorganizationSubstantiv | Substantiv |
| organizátororganizerSubstantiv | Substantiv |
| organizovatorganizeVerb | Verb |
| orchestrorchestraSubstantiv | Substantiv |
| orientaceorientationSubstantiv | Substantiv |
| orientačníapproximate; orientationalAdjektiv | Adjektiv |
| origináloriginalSubstantiv | Substantiv |
| originálníoriginalAdjektiv | Adjektiv |
| orlicefemale eagleSubstantiv | Substantiv |
| oslavacelebrationSubstantiv | Substantiv |
| oslavitcelebrateVerb | Verb |
| oslovovataddress; speak toVerb | Verb |
| osmeightZahl | Zahl |
| osmažitfry lightly; fryVerb | Verb |
| osmdesáteightyZahl | Zahl |
| osmdesátá létathe eighties; the 1980sPhrase | Phrase |
| osmnácteighteenZahl | Zahl |
| osmnáctýeighteenthZahl | Zahl |
| osobapersonSubstantiv | Substantiv |
| osobněpersonally, in personAdverb | Adverb |
| osobnípersonalAdjektiv | Adjektiv |
| osobní dokladidentity documentWortkombination | Wortkombination |
| osobnostpersonalitySubstantiv | Substantiv |
| osprchovat setake a showerVerb | Verb |
| ostatníotherAdjektiv | Adjektiv |
| ostrovislandSubstantiv | Substantiv |
| ostrýsharp; spicyAdjektiv | Adjektiv |
| ostříhatcut hair; trimVerb | Verb |
| ostýchavýshyAdjektiv | Adjektiv |
| OSVČosvčself-employed personWortkombination | Wortkombination |
| ošetřittreat; attend toVerb | Verb |