What does the cryptic crossword clue "Mafioso robs Met violently (7)" mean?

The definition is "Mafioso". The wordplay uses an anagram. anagram of ROBS + MET = MOBSTER; definition: "Mafioso" The answer is MOBSTER.

Mafioso robs Met violently (7)

Daily Mail Cryptic #16521 | 1 Across | 2021-02-26 flower