Source : Webster's Revised Unabridged Dictionary (1913)

Gliff \Gliff\, n. [Cf. OE. gliffen, gliften, to look with fear
   at.]
   1. A transient glance; an unexpected view of something that
      startles one; a sudden fear. [Prov. Eng. & Scot.]
      --Halliwell.

   2. A moment: as, for a gliff. [Scot.] --Sir W. Scott.