Denshi Jisho — Online Japanese dictionary

忽焉 こつえん sudden; unexpected
Taru-adjective, Adverb taking the 'to' particle 
終焉 しゅうえん demise
Common word, Noun 
焉んぞ いずくんぞ how; why
Interjection, Usually written using kana alone 
烏焉魯魚 うえんろぎょ miswriting a word; using the wrong kanji to write a word
Noun 
心焉に在らず こころここにあらず there in body, but not in spirit; distracted; in one ear and out the other
Expression 
心焉に在らざれば視れども見えず こころここにあらざればみれどもみえず The eye is blind if the mind is absent
Expression, Idiomatic expression 

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