Longtermer is a term used to refer to someone or something that has been in a particular situation, position or place for a significant period. Antonyms for this word can be used to describe something that is short term or temporary. These antonyms include words like ephemeral, fleeting, momentary, brief, short-lived, and transitory. These words often connote a sense of impermanence or transience, rather than the enduring quality of something that is long term. In contrast to longtermer, words like transient, passing, impermanent, and fleeting suggest that something is only temporary, or that it will soon come to an end.