Sama-sīsī: one 'who attains two ends simultaneously', namely: the ceasing of fermentations and the end of life see: Pug. 19. In A. VIII, 6 it is said: Such is the case with a Bhikkhu who dwells in the contemplation of impermanency of all forms of existence, keeping before his eyes their impermanency, perceiving their impermanency, perseveringly, steadfastly, undisturbed, of firm mind, wisely absorbed; and in whom at one and the same time the ceasing of fermentations and the end of like take place.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.