What does the cryptic crossword clue "One who purposely wrecks boat sure must change (8)" mean?

The definition is "One". The wordplay uses an anagram. anagram of BOAT (synonym="BOAT") + SURE (synonym="SURE") = SABOTEUR The answer is SABOTEUR.

One who purposely wrecks boat sure must change (8)

Independent Cryptic #11914 | 10 Across | 2024-12-16 flower