What does the cryptic crossword clue "It's glee that's out of place for mournful writer (7)" mean?

The definition is "writer". The wordplay uses an anagram. anagram of IT'S + GLEE = ELEGIST; definition: "writer" The answer is ELEGIST.

It's glee that's out of place for mournful writer (7)

Daily Mail Cryptic #17031 | 23 Across | 2023-02-10 flower