What does the cryptic crossword clue "Terrible triteness has the capacity to fascinate (9)" mean?

The definition is "fascinate". The wordplay uses an anagram. anagram of TRITENESS = INTERESTS; definition: "fascinate" The answer is INTERESTS.

Terrible triteness has the capacity to fascinate (9)

Guardian Cryptic #29187 | 16 Down | 2023-09-28 flower