From moment + -ous .
momentous (comparative more momentous , superlative most momentous )
Outstanding in importance , of great consequence .
1725 , Daniel Defoe , Everybody's Business is Nobody's Business :The reason why I did not publish this book till the end of the last sessions of parliament was, because I did not care to interfere with more momentous affairs.
1831 , James Fenimore Cooper , chapter 31, in Homeward Bound :"It has been a momentous month, and I hope we shall all retain healthful recollections of it as long as we live."
1902 , Joseph Conrad , chapter 3, in The End of the Tether :What to the other parties was merely the sale of a ship was to him a momentous event involving a radically new view of existence.
2007 July 1, Richard Dawkins , “Inferior Design ”, in New York Times , retrieved 19 November 2013 :Natural selection is arguably the most momentous idea ever to occur to a human mind, because it — alone as far as we know — explains the elegant illusion of design that pervades the living kingdoms and explains, in passing, us.
of outstanding importance or great consequence
Arabic: جَسِيم (ar) ( jasīm )
Armenian: կարևոր (hy) ( karewor )
Old Armenian: մեծ ( mec )
Azerbaijani: mühüm (az)
Basque: erabakigarri , garrantzitsu
Bulgarian: много важен (bg) ( mnogo važen )
Catalan: crucial (ca) , crític (ca) m , decisiu (ca) m , definitiu (ca) m , significatiu (ca) m
Czech: důležitý (cs) m , významný (cs) m , závažný (cs) m
Esperanto: gravega
Estonian: pöördeline (et)
Finnish: merkittävä (fi) , merkityksellinen (fi) , järisyttävä (fi) , käänteentekevä
French: capital (fr) , considérable (fr) , fatidique (fr) , primordial (fr) m , essentiel (fr) m , substantiel (fr) m
Galician: momentoso m , capital (gl) , crucial , primordial (gl) , transcendental
German: wichtig (de) , bedeutsam (de) , folgenreich (de) , folgenschwer (de) , denkwürdig (de) , gewichtig (de)
Hebrew: חשוב (he) m ( khashuv ) , רב חשיבות m ( rav khashivut )
Hungarian: jelentős (hu) , nagy jelentőségű /horderejű
Ido: grava (io) , importanta (io)
Italian: cruciale (it) m or f , critico (it) m , importante (it) m or f , fondamentale (it) m or f , epocale (it) m or f
Japanese: 重大な (ja) ( じゅうだいな, jūdai na )
Korean: 중대하다 (ko) ( jungdaehada )
Latin: magnus (la) m
Manx: frioosagh
Occitan: important (oc) , considerable (oc) , capital (oc) , essencial (oc) , fondamental (oc)
Polish: doniosły (pl) m , ważny (pl) , znaczący (pl) , wielkiej wagi m
Portuguese: momentoso m , capital (pt) , crítico (pt) m , crucial (pt) , importante (pt) m or f , memorável (pt)
Romanian: însemnat (ro)
Russian: ва́жный (ru) ( vážnyj ) , знаменательный (ru) ( znamenatelʹnyj )
Sanskrit: गुरु (sa) ( guru )
Spanish: importante (es) , crucial , memorable (es)
Swedish: betydelsefull (sv) , viktig (sv)
Turkish: mühim (tr) , önemli (tr)
Vietnamese: quan trọng (vi) , trọng yếu (vi)