What does the cryptic crossword clue "Messing about on or close to barge sure is wrong (9)" mean?

The definition is "wrong". The wordplay uses an anagram. anagram of ON OR E SURE = ERRONEOUS; definition: "wrong" The answer is ERRONEOUS.

Messing about on or close to barge sure is wrong (9)

Times Cryptic #28629 | 7 Down | 2023-06-14 flower