What does the cryptic crossword clue "Musician in suit, flat unfortunately (8)" mean?

The definition is "Musician". The wordplay uses an anagram. anagram of SUIT, + FLAT = FLAUTIST; definition: "Musician" The answer is Flautist.

Musician in suit, flat unfortunately (8)

Telegraph Prize Cryptic #3045 | 5 Across | 2020-03-01 flower