The last works of the French impressionist painter Claude Monet...painted at his home at Giverny, show this brunescent change over time. Monet's right cataract was removed in January, 1923, and works painted after this time show a return of the blues and violets to his artistic palette

Evidently it means tending to red or brownish. But I don't find it in OneLook. Why not

dalehileman