syllabub

noun

1. 1

   A drink dating back to the 16th century consisting primarily of milk curdled with an alcoholic beverage or some acid such as lemon juice, which is usually then sweetened and spiced.

2. 2

   Also everlasting syllabub or solid syllabub: a dessert pudding derived from the drink.

3. 3

   Something lacking substance; something frothy, insubstantial, or lightweight.