What does the cryptic crossword clue "Car goes around in gear just over bottom (10)" mean?

The wordplay uses a charade (building blocks). MINI (synonym="car") + SKIRTS (synonym="goes around") = MINISKIRTS The answer is MINISKIRTS.

Car goes around in gear just over bottom (10)

Guardian Cryptic #25714 | 8 Down | 2012-08-14 flower