fleeting
1. [ adjective ] moving or passing by very swiftly
Examples:

"fleeting clouds passing before the face of the moon"

Related terms: moving
2. [ adjective ] lasting for a markedly brief time
Synonyms: momentary momentaneous fugitive
Examples:

"a fleeting glance" "fugitive hours" "rapid momentaneous association of things that meet and pass" "a momentary glimpse"

Related terms: short
Similar spelling:   fluting
  floating
  flooding