undate means undated; rising and falling in waves. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
From Latin undātus.
adj
- undated; rising and falling in waves
noun
- A casual meeting arranged between two people that may resemble a date (romantic outing) but is not intended as one.“[…] an undate, all you're really doing is hanging out with a new acquaintance for a few hours.”