Source : Webster's Revised Unabridged Dictionary (1913)

Sickerness \Sick"er*ness\, Sikerness \Sik"er*ness\, n.
   The quality or state of being sicker, or certain. [Obs.]
   --Chaucer. Spenser.

Siker \Sik"er\, a. & adv., Sikerly \Sik"er*ly\, adv., Sikerness
\Sik"er*ness\, n., etc.
   See 2d {Sicker}, {Sickerly}, etc. [Obs.]