What does the cryptic crossword clue "Part of speech on boring new Louvre painter (8,7)" mean?

The wordplay uses an anagram. anagram of ON + LOUVRE + PAINTER = RELATIVEPRONOUN The answer is RELATIVEPRONOUN.

Part of speech on boring new Louvre painter (8,7)

Daily Mail Cryptic #16246 | 2 Down | 2020-02-07 flower