CHOOSE THE RIGHT WORD (temporary, ephemeral, evanescent, fleeting, transient, transitory) from the Thesaurus in my Mac laptop

temporary, ephemeral, evanescent, fleeting, transient, transitoryThings that don't last long are called temporary, which emphasizes a measurable but limited duration (a temporary appointment as chief of staff). Something that is fleeting passes almost instantaneously and cannot be caught or held (a fleeting thought; a fleeting glimpse). Transient also applies to something that lasts or stays only a short time (transient house guests), while transitory refers to something that is destined to pass away or come to an end (the transitory pleasure of eating). Evanescent and ephemeral describe what is even more short-lived. Ephemeral literally means 'lasting for only a single day,' but is often used to describe anything that is slight and perishable (his fame was ephemeral). Evanescent is a more lyrical word for whatever vanishes almost as soon as it appears. 
In other words, a job might be temporary, an emotion fleeting, a visitor transient, a woman's beauty transitory, and glory ephemeral, but the flash of a bird's wing across the sky would have to be called evanescent.