wild card

1. 1.

   an unpredictable factor

   “the weather was a wild card”

   Broaderfactor
2. 2.

   a playing card whose value can be determined by the person who holds it

   Broaderplaying card

Questions about wild card

What does wild card mean?

wild card means "an unpredictable factor". That is the primary sense; the word has 2 in total, listed in full on this page.

Is wild card a common word?

wild card is banded "Uncommon" — turns up in careful writing rather than conversation. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.