The infirmity of old age - Caducity (नश्वरता)
A man devoid of kind feeling and sympathy - Callous (कठोर, निष्ठुर)
A man or animal that feeds on its own species - Cannibal (नरभक्षी)
Belonging or pertaining to an individual from birth - Congenital (जन्मजात)
An assembly of worshippers - Congregation (सभा)