Coined some time during Middle English out of existing English roots. It is now, alas, thoroughly obsolete, and only appears in unabridged dictionaries only, I suspect, because it appears in the 1551 Tyndale Bible (predecessor of the King James translation) and so needs to be explained. Compare also the equally obsolete ereyesterday.
La, 'tis indeed our intent, Sir Roderick, to visit the beach overmorrow -- would'st thou sport with us?
(Note: that's a deliberate mashup of idioms from different periods. No one, ever, spoke like that.)
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