Archaic third-person singular form of 'come'; an old-fashioned way to say 'comes' (he/she/it comes).
From Old English 'cumeth,' where '-eth' was the standard verb ending in Early Modern English (the language of Shakespeare and the King James Bible) for third-person singular present tense.
'Cometh' sounds biblical because it IS—the '-eth' ending disappeared from English around the 1700s, but it lives on in the King James Bible's famous phrases like 'he cometh' which make it sound mysteriously ancient and formal.
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