un ‧ told /ˌʌnˈtəʊld◂ $ -ˈtoʊld◂/ BrE AmE adjective [only before noun]
1 . used to emphasize how bad something is:
The rumours will do untold damage to his reputation.
The floods have caused untold misery to hundreds of homeowners.
2 . used to emphasize that an amount or quantity is very large
untold riches/wealth
a game that offers untold wealth to the most talented players