Wild card is a special invitation that is given to someone for exceptional merit, contrary to rules and ratings. In literal translation from English, "wild card" means "wild card". The meaning of the expression is that such an invitation is not subject to strict criteria and can be issued to any person at the whim of the organizers.
In the big tennis there is a strict selection for the main competitions, however in each of the tournaments there are 2-3 "free places" to which the organizers can invite a tennis player who did not show good results in the current season but who has great merits before the world tennis or who submits big hope.
An example of use: "Maria Sharapova received a wild card for participation in the Kremlin Cup in 2017".
Wild card is in the list: Sports