What does the cryptic crossword clue "Proficient testament to benevolence (8)" mean?

The wordplay uses a charade (building blocks). GOOD (synonym="=proficient, able") + WILL (synonym="=testament") = GOODWILL The answer is GOODWILL.

Proficient testament to benevolence (8)

Independent Cryptic #11653 | 17 Down | 2024-02-15 flower