An obsolete or archaic variant of 'aloof,' meaning at a distance or keeping away.
From Middle English and Old English, possibly from Dutch 'a-loof' (on the lee side of a ship). The '-out' form is an archaic variant showing how 'a-' prefix words shifted meanings.
Medieval English had tons of 'a-' prefix words like 'aloud,' 'alight,' 'aflame'—they're like frozen fossils showing us how English used to build words differently. Most are gone now, except we still say 'aloof.'
Complete word intelligence in one call. Free tier — 50 lookups/day.