Literally: Sing like a saucepan
Meaning: Sing flat; Someone who really can’t sing; To be unable to carry a tune in a bucket.
Origins: 20th century, coined by the writer Leon Bloy (1846-1917) in 1907, when he declared that the saucepans banging against each other are as bad as a bad singer.
Synonyms: chanter comme une seringue;
Examples: Papa dis toujours que je chante comme une casserole/
Dad says I can’t carry a tune in a wheelbarrow