and all this time I thought it was a noun, an old-timey drink.
It's both:
Noun
wassail (plural wassails)
A toast to health, usually at a festival.
The beverage served during a wassail, especially one made of ale or wine flavoured with spices, sugar, roasted apples, etc.
Revelry. [quotations ▼]
A festive or drinking song or glee. [quotations ▼]
Translations
[show ▼]beverage served during a wassail
Verb
wassail (third-person singular simple present wassails, present participle wassailing, simple past and past participle wassailed)
(transitive) To toast, to drink to the health of another.
The next morning he much regretted the gusto with which he had wassailed the night before.
(intransitive) To drink wassail.
To go from house to house at Christmastime, singing carols.