foxed

1. To trick, fool or outwit (someone) by cunning or ingenuity.
2. To confuse or baffle (someone).

   This crossword puzzle has completely foxed me.

3. To act slyly or craftily.
4. To discolour paper. Fox marks are spots on paper caused by humidity. (See foxing.)

   The pages of the book show distinct foxing.

5. To make sour, as beer, by causing it to ferment.
6. To turn sour; said of beer, etc., when it sours in fermenting.
7. To intoxicate; to stupefy with drink.
8. To repair (boots) with new front upper leather, or to piece the upper fronts of.

adjective

Of paper, having yellowish-brown stains.