‘His name is not uttered. It must not be mentioned ; only indirectly is He to be referred to’ [Shivam to Shūnyam].
Vishnu has a thousand names [Sahasranāma] precisely because He is Nameless.
You can find ‘Nameless’ in every religious tradition, sometimes upfront, sometimes tucked away in a footnote. But there is no serious tradition that does not carry it, or some close variant of it, in its texts and practice.
Point a finger, draw a line, say a word, think a thought, emote a feeling towards the ‘Nameless’ and by that very act, what you have pointed a finger to, drawn a line of, said, thought, emoted, is not the ‘Nameless’.
Is ‘Nameless’ a name? Or is it not a name? Try it.
The answer is, it is neither: ‘Nameless’ is a Self-Eating Expression [‘SEE’].
The Lady doesn’t like to be called names.