transient

Passing or disappearing with time; transitory.

a transient pleasure

this transient world

Remaining for only a brief time.

a transient view of a landscape

a transient disease

Decaying with time, especially exponentially.

having a positive probability of being left and never being visited again.

Occasional; isolated; one-off

Something that is transient.

A transient phenomenon, especially an electric current; a very brief surge.

A relatively loud, non-repeating signal in an audio waveform that occurs very quickly, such as the attack of a snare drum.

A person who passes through a place for a short time; a traveller; a migrant worker.

Then, within the space of a few months, there were more transients than there were locals, and the imbalance seemed morally wrong.

A homeless person.