What does the cryptic crossword clue "To appear servile in civil war, Cavaliers effecting volte-face (5)" mean?

The wordplay uses hidden reversed. hidden reversed in "civil war, Cavaliers" The answer is CRAWL.

To appear servile in civil war, Cavaliers effecting volte-face (5)

Guardian Cryptic #23582 | 17 Across | 2005-10-11 flower