The Collaborative International Dictionary
Sikerness
Siker \Sik"er\, a. & adv., Sikerly \Sik"er*ly\, adv., Sikerness \Sik"er*ness\, n., etc. See 2d Sicker, Sickerly, etc. [Obs.]
Sikerness
Sickerness \Sick"er*ness\, Sikerness \Sik"er*ness\, n.
The quality or state of being sicker, or certain. [Obs.]
--Chaucer. Spenser.
Wiktionary
sikerness
n. (context obsolete English) certainty