What does the cryptic crossword clue "Thin plate unsatisfactory all turned upside down (7)" mean?

The definition is "Thin plate". The wordplay uses a reversal. LAME (synonym="unsatisfactory") + ALL (reversal="ALL") = LAMELLA The answer is LAMELLA.

Thin plate unsatisfactory all turned upside down (7)

Independent Cryptic #12050 | 7 Down | 2025-05-23 flower