Long-legged wader (4)
I believe the answer is:
'long-legged wader' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ibis that I've seen before include "Large wading birds with down-curved bills" , "Long-legged wading bird" , "State of central US, capital Lincoln" , "Bird sacred in Ancient Egypt" , "Retreat" .)