Broke or came off in thin layers, or in slang, abandoned plans or failed to show up.
From 'flake,' possibly from Old Norse 'flak' (a piece broken off). The verb form uses the -ed suffix for past tense.
When someone 'flakes out' on you, the word perfectly captures what happens—they break apart from their commitment, fluttering away like a snowflake. The metaphor is built into the slang.
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