What does the cryptic crossword clue "Good idea waving with an arm, as he got away with it! (5,8)" mean?

The wordplay uses an anagram. anagram of GOOD + IDEA + AN + ARM, = DIEGOMARADONA The answer is DIEGOMARADONA.

Good idea waving with an arm, as he got away with it! (5,8)

Guardian Cryptic #23907 | 10 Down | 2006-10-26 flower