The Collaborative International Dictionary of English v.0.48:
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. [1913 Webster] 2. A moment: as, for a gliff. [Scot.] --Sir W. Scott. [1913 Webster]