What does the cryptic crossword clue "Can't rude jockeys perform with some restraint? (8)" mean?

The wordplay uses an anagram. anagram of CAN'T + RUDE = UNDERACT The answer is UNDERACT.

Can't rude jockeys perform with some restraint? (8)

Times Cryptic #29016 | 16 Down | 2024-09-07 flower