pot luck British English , pot‧luck American English
to choose something without knowing very much about it, and hope that it will be what you want:
We hadn't booked a hotel so we had to take pot luck.
to have a meal at someone's home in which you eat whatever they have available, rather than food which has been specially bought for the occasion:
I'm not sure what there is in the fridge - you'll have to take pot luck.
2 [countable] American English
a meal in which everyone who is invited brings something to eat:
Can you bring a salad? It's a potluck.
potluck meal/dinner etc
a potluck supper at the church