Sickerness

Origin

From sicker + -ness.

Full definition of sickerness

Noun

1. (obsolete) Certainty, assurance.
2. (obsolete) Security, safety, freedom from danger.
• 1590, Edmund Spenser, The Faerie Queene, III.vii:Lightly she leaped, as a wight forlore,
  From her dull horse, in desperate distresse,
  And to her feet betooke her doubtfull sickernesse.