| fly-by-night(adjective, short, unreliable, brief, shady) |
| volatile(adjective, present, short, brief, immediate) |
| unstable(adjective, present, short, limited, brief) |
| short-term(adjective, present, continue, short, limited) |
| alternate(adjective, present, short, substitute, replacement) |
| changeable(adjective, present, short, unstable, limited) |
| mortal(adjective, transient, transientness) |
| pro tem(expression, adjective, continue, short, substitute) |
| provisory(adjective, transientness) |
| temp(noun, adjective, reserve, replacement, alternative) |
| ad interim(expression, adjective, idiom, continue, substitute) |
| fading(adjective, brief, transient, transitory, short-lived) |
| flitting(adjective, short, brief, transient, transitory) |
| tentative(adjective, new, unsettled, extra, trial) |
| perishable(adjective, present, short, immediate, instant) |
| improvised |
| limited |
| meteoric(adjective, brief, momentary, transitory, short-lived) |
| ad hoc(expression, adjective, idiom) |
| cursory(adjective, time, brief, transient, transitory) |