a card having its value decided by the wishes of the players.
a determining or important person or thing whose qualities are unknown, indeterminate, or unpredictable: In a sailboat race the weather is the wild card.
a player, usually without ranking, who is allowed to enter a tournament at the discretion of the tournament committee after regularly qualifying competitors have been selected.
of, being, or including an unpredictable or unproven element, person, item, etc.
of, being, or including an unseeded or unproven participant or team, as a team in a championship tournament that has not placed first in its league or area.