What does the cryptic crossword clue "Walker is one with no answer for parasites (4)" mean?

The definition is "parasites". The wordplay uses a deletion. LICE (deletion) = LICE; definition: "parasites" The answer is LICE.

Walker is one with no answer for parasites (4)

Guardian Cryptic #29640 | 24 Across | 2025-03-12 flower