what's-her-name

noun[in the plural]1

1. •
   (informal, disapproving) A passing (female) acquaintance of no importance or relevance.

pronoun1

1. •
   (informal) A woman whose identity is unknown or forgotten (especially when better-known to the listener).

noun[in the plural]1

1. •
   (informal, disapproving) A passing (male) acquaintance of no importance or relevance.

pronoun1

1. •
   (informal) A man whose identity is unknown or forgotten (especially when better-known to the listener).

   • I left his arm that night myself / For what's-his-name's, the new prose-poet / Who wrote the book there, on the shelf — 1842

noun[in the plural]1

1. •
   (informal, disapproving) A passing acquaintance of no importance or relevance.

pronoun1

1. •
   (informal) A person whose identity is unknown or forgotten (especially when better-known to the listener).