Wild card refers to an element or factor that is unpredictable or unknown. There are several synonyms for the word "wild card", such as uncertainty, unpredictability, ambiguity, chance, and surprise factor. Another word that can be used as a synonym is "variable". In sports, the term "dark horse" can also be used to describe a wild card team or player that unexpectedly performs well in a tournament or competition. Other synonyms for wild card in a sporting context include "underdog", "long shot", and "outlier". The term "curveball" can also be used as a synonym for a wild card, which is a sudden or unexpected change that can impact a situation.