transient

Adjective

• lasting a very short time
  • the ephemeral joys of childhood
    
  • a passing fancy
    
  • youth's transient beauty
    
  • love is transitory but it is eternal
    
  • fugacious blossoms
    

• of a mental act; causing effects outside the mind

Noun

• (physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load

• one who stays for only a short time
  • transient laborers
    

Related words

• Synonyms: 
  ephemeral , passing , short-lived , transitory , fugacious , transeunt
• Antonyms: 
  immanent , subjective