Noun. A heavy meal served with alcohol before brunch, usually after an evening of heavy drinking, designed to make an individual presentable for a midday event, like brunch. Etymology: pre- + brunch.
Also, intransitive verb. To consume prunch with or without enjoyment.
(1) He isn't sure he would have made it through brunch if he hadn't brunched beforehand. (2) I think I would like a pizza for prunch, since there may not be food served at the brunch.