short-timer

/SH AO1 R T AY0 M ER0/
noun
  1. 1

    A soldier during the Vietnam war who had less than two months to serve.

  2. 2

    A person who would not be required to do a difficult or dangerous task.

  3. 3

    An employee who has given notice of their intent to leave.

Source: https://en.wiktionary.org/wiki/short-timer