Documented: orang, person, people, plus hutan, forest, jungle. The word appears in Malay and Old Javanese sources predating European contact. The earliest attested European usage applied orang-outang to humans, and Jacobus Bontius's 1631 account applied it to the ape, possibly mishearing or possibly recording local speech accurately, Malay speakers applied the word to both, and the ambiguity is in the sources themselves.
The reading the compound forces: Malay folklore carries the forest-person category in figures like the mawas and orang pendek, and the ape inherited a name from a category that included legendary beings. The ape and the wild man share a word because they shared a conceptual slot, the person-shaped thing outside the village.
The modern echo: the orangutan's scientific name, Pongo, comes from a Kikongo word for gorilla, so the species carries a name meaning forest-person from the wrong continent and a Latin binomial borrowed from the wrong ape. Taxonomy's most thoughtful genus is named, twice, by rumor.
When a word meant forest person, who was living in the forest?