WILDCARD

Unpredictable factor (4,4)

Solution has appeared in 2 crosswords (1 across and 1 down):

• Quick crossword No 16,284 — 2022-07-15 23:00:51
  2D: Player invited to compete, though not formally qualifying (4,4)
• Quick crossword No 15,203 — 2019-01-29 00:00:17
  19A: Unpredictable factor (4,4)