Quinn comes from the Irish surname O Cuinn, often traced to a root meaning "wisdom" or "counsel" -- originally a family name long before it became a given name. As a unisex choice today, it tends to carry a sense of directness: someone whose judgment is trusted without much ceremony around it.
Immobility of a slow celestial body is more efficient than the dynamism of a quick one, even though they have the same strength. - Picatrix (Andalusia, ~1000.AD)