What does the cryptic crossword clue "Actor Merle serious about refusing lead (6)" mean?

The wordplay uses a charade (building blocks). OBER (synonym="OBER") + ON (synonym="1911-1979") = OBERON The answer is OBERON.

Actor Merle serious about refusing lead (6)

Independent Cryptic #11470 | 2 Down | 2023-07-17 flower