Pot luck is taking whatever happens to be available. Take pot luck.
The image is arriving unannounced and eating whatever is in the pot. In America a pot luck is a meal where every guest brings a dish, which is a different thing.
1nounpot luckTaking whatever happens to be available.
“They took pot luck on a hotel and were lucky.”
pot luck is a chance.
potluck comes from pot + luck. According to the Oxford English Dictionary, sense 3 (“a shared meal consisting of whatever guests have brought”) is unlikely to have been influenced by potlatch.
Etymology from Wiktionary, CC BY-SA