nonce

n. [ For the nonce, OE. for the nones, a corruption of for then ones, where n. in then is a relic of AS. m in ðam, dat. of the article and demonstrative pronoun, E. the. See For, Once, and The. ] The one or single occasion; the present call or purpose; -- chiefly used in the phrase
for the nonce, i. e. for the present time. [ 1913 Webster ]

The miller was a stout carl for the nones. Chaucer. [ 1913 Webster ]

And that he calls for drink, I 'll have prepared him
A chalice for the nonce. Shak. [ 1913 Webster ]

Nonce word, “a word apparently employed only for the nonce”. Murray (New English Dict.). [ 1913 Webster ]