LordWarfire

I would say it means strong but with an implied sadness, but you can have positive poignant memories too - you’d just have to state they were positive. The day I graduated from University was poignant because it was the end of an era and the start of another, but it doesn’t mean it is a sad memory.

Nonce as an insult is definitely used in British, although it has a very specific meaning so not something you’d casually call a friend (depending on the friend!)