What does the cryptic crossword clue "Furtive, engaging creditor on the slightest basis (9)" mean?

The wordplay uses a container (one word inside another). LENDER (synonym="creditor") in SLY (synonym="furtive") = SLENDERLY The answer is SLENDERLY.

Furtive, engaging creditor on the slightest basis (9)

Independent Cryptic #12002 | 18 Across | 2025-03-28 flower