What does the cryptic crossword clue "Tedium something of an unspoken nuisance (5)" mean?

The definition is "Tedium". The wordplay uses a hidden word. Hidden in "tedium something of an unspokEN NUIsance" The answer is ENNUI.

Tedium something of an unspoken nuisance (5)

Times Cryptic #29038 | 17 Across | 2024-10-03 flower