What does the cryptic crossword clue "Egg layer had nice waves (7)" mean?

The definition is "Egg layer". The wordplay uses an anagram. anagram of HAD + NICE = ECHIDNA; definition: "Egg layer" The answer is ECHIDNA.

Egg layer had nice waves (7)

Guardian Cryptic #29134 | 28 Across | 2023-07-28 flower