Sanskrit Sacred texts are Apauruṣeya, a word routinely and literally interpreted as ‘Not authored by Man’, that is, like the Koran or the Bible, the direct ‘Word of God’.
That is not what the word is meant to suggest. Apauruṣeya denotes something not ‘Man-Made’, that is not a creation of a Modeled-Interpretation, a delineation extended in the Sruti/Smriti distinction.
The Kanchi Paramacharya [1894-1994], holder of the lineage-seat of Śaṅkarācārya and a modern authority on the subject, explains that the proper name for Hinduism is simply as the ‘Nameless’.
Vishnu has a thousand names [Sahasranāmam] precisely because Vishnu is Nameless. [So does Allah in Arabic but it is interpreted differently by the Mullahs.]
The word ‘Nameless’ is simultaneously a name and a noun and an adjective about itself as a name and a noun.
Is ‘Nameless’ a name? Or is it not a name? [Try it.] A meta-statement, a self-referential swivel, it has the same Logical Form as ‘That’ and the Tao.
The name ‘Hindu’ is relatively recent and is largely unknown in Sanskrit text. It almost certainly originates as the Persian/ Greek transform of a label for people ‘Living east of the river Sindhu’ [where the ‘S’ becomes ‘H’ and ‘I’, as in the river Indus] .
The nearest original word Dharma is a complex term and not easily translated. [I have a lengthy Post on ‘The Freedom To Speak’ surveying the breath of this Tradition through history. It’s not up yet.]