Proto-Tungus-Manchu: *čiK-
Meaning: grown-up
Russian meaning: возмужалый, совершеннолетний (о мужчине от 30 до 40 лет)
Literary Manchu: čiqsin
Comments: ТМС 2, 392. Attested only in Manchu, but quite possibly going back to the Altaic root for 'time' (*'timely' > 'grown-up').