A Dummy candidate is a candidate who stands for election

Election

An election is a formal decision-making process by which a population chooses an individual to hold public office. Elections have been the usual mechanism by which modern representative democracy operates since the 17th century. Elections may fill offices in the legislature, sometimes in the...

 with no intention of winning but to direct preferences to other candidates in order to increase their share of the vote.

The term can also refer to a candidate who stands under a similar name as a more established candidate so as to damage the other genuine candidate.