incertitude
n.
mid-15c., "variability," from Middle French incertitude (14c.), from Late Latin incertitudinem (nominative incertitudo); see certitude. Incertain "uncertain" and incertainty "uncertainty" also were living words in Middle English.
〔蒋〕[in-不，cert确实，确信，] 不确定，不肯定，无把握