Who are you looking for? There's no one here by that name.
Tips
usage
Default phone/door-answering question once it's clear the caller hasn't reached who they expected. 谁 is read shéi in conversation, though dictionary form is shuí — both are correct.
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Bare 找谁? on its own can sound curt. Soften with the polite frame 请问您找谁? — adding 请问 ('may I ask') and the honorific 您 makes it appropriate for strangers and customers.
