Lame duck

Lame duck is a term used to describe an elected politician who will soon be leaving office. It is used for those leaving either because the have held the office for the most terms they are allowed to (term limit) or because they have lost an election. Because they are not seen to still have much remaining power, lame duck politicians will often not get much done. They sometimes make decisions that many people do not agree with because they know the decision will not make them lose an election.
For example, a US President is said to be a lame duck president during their second term as President because they can only be President for two terms. If they lose the election to stay as the President for a second term, they are also seen as a lame duck from the time the election results are final until January 20 of the next year when the winner of the election becomes President.