fugacious (adj.)

• brittle
• capricious
• changeable
• corruptible
• deciduous
• dying
• ephemeral
• evanescent
• fading
• fickle
• fleeting
• fly-by-night
• flying
• fragile
• frail
• fugitive
• impermanent
• impetuous
• impulsive
• inconstant
• insubstantial
• momentary
• mortal
• mutable
• passing
• perishable
• short-lived
• temporal
• temporary
• transient
• transitive
• transitory
• unstable
• volatile