pre-noun adjectival
completely unknown; unfamiliar; complete stranger
Pre-noun adjectival (rentaishi) used to describe people or things that are entirely unknown or unfamiliar. Often appears in set phrases like 見も知らぬ人.
見も知らぬ人から手紙が届いた。
I received a letter from a complete stranger.
彼は見も知らぬ土地で道に迷った。
He got lost in a completely unfamiliar place.
知らない is a general verb meaning 'don't know'; 見も知らぬ is a fixed pre-noun modifier emphasizing total unfamiliarity, often with a nuance of 'never seen before'.
見知らぬ is a similar pre-noun adjectival meaning 'unknown' or 'unfamiliar', but 見も知らぬ adds emphasis with も, implying 'even seeing is not known'.
Compound of 見 (mi, 'seeing') + も (mo, 'even') + 知らぬ (shiranu, classical negative of 知る 'to know'). Literally 'even seeing, not knowing', i.e., completely unknown.