What does the cryptic crossword clue "Old princess has upset a servant (8)" mean?

The definition is "Old princess". The wordplay uses an anagram. anagram of A + SERVANT = TSAREVNA; definition: "Old princess" The answer is TSAREVNA.

Old princess has upset a servant (8)

Times Cryptic #28784 | 18 Across | 2023-12-12 flower