The person who attained enlightenment is called 'Buddha,' a name that was transliterated into Kanji; it is pronounced 'Buddha' or 'Butsu' and is also paraphrased as 'the enlightened one, Kakusha.'
悟りを開いた者を「buddhaブッダ」といい、漢字で音写し「仏陀」「仏」としたり、「覚者」と意訳したりする。