What does the cryptic crossword clue "What’s inhaled by queen – king’s rolling a joint (4)" mean?

The definition is "joint". The wordplay uses a hidden word. Hidden reversed in "what’s inhaled by quEEN – King’s rolling a joint" The answer is KNEE.

What’s inhaled by queen – king’s rolling a joint (4)

Guardian Cryptic #29395 | 4 Down | 2024-05-29 flower