whats-er-name; whats-her-name noun used to refer to a name that is unknown, forgotten, to be avoided or hardly worth mentioning UK
There’s this café, you see, opposite the motel, called the Jubilee, opposite whats-er-name street[.] — Paul E Willis, ProfaneCulture, p. 37, 1978
Why the Hell did Ray ever bring that bloody article on Clare Whatshername! [...] Don’t pretend you don’t know her full name. — Stuart Browne, DangerousParking, p. 149, 2000