fleeting

transient, transitory, ephemeral, momentary, fugitive, fleeting, evanescent mean lasting or staying only a short time. transient applies to what is actually short in its duration or stay <a hotel catering primarily to transient guests>. transitory applies to what is by its nature or essence bound to change, pass, or come to an end <fame in the movies is transitory>. ephemeral implies striking brevity of life or duration <many slang words are ephemeral>. momentary suggests coming and going quickly and therefore being merely a brief interruption of a more enduring state <my feelings of guilt were only momentary>. fugitive and fleeting imply passing so quickly as to make apprehending difficult <let a fugitive smile flit across his face> <fleeting moments of joy>. evanescent suggests a quick vanishing and an airy or fragile quality <the story has an evanescent touch of whimsy that is lost in translation>.