Noun
(philosophy, existentialism, Kierkegaardianism) Personal despair over the disquieting circumstances of human existence.
(by extension) Despair, profound discontent, or a similar persistent debilitating malaise of the mind, spirit, or soul that produces a decline in mental, physical, or societal health and that may culminate in death or dissolution.
Source: en.wiktionary.orgReturn unto thy rest, my soul, From all the wanderings of thy thought, From sickness unto death made whole, Safe through a thousand perils brought. James Montgomery
... because man has been created in God's image, sin is not natural. Sin is the deformation of man, it is a cancer, it is a sickness unto death which has infected man. Rousas John Rushdoony