What does the cryptic crossword clue "Obnoxious type of quiet Scottish island (6)" mean?

The wordplay uses a charade (building blocks). SH (synonym="quiet!") + MUCK (synonym="Hebridean island") = SHMUCK The answer is SHMUCK.

Obnoxious type of quiet Scottish island (6)

Guardian Cryptic #29226 | 20 Down | 2023-11-13 flower