MEANING:
noun: Something having both good and bad parts.
ETYMOLOGY:
From a cartoon in Punch magazine (London, UK) in which a timid curate (a junior clergy member), when served a stale egg at a bishop's table, tries to assure his host that parts of the egg are edible. Earliest documented use: 1905.
USAGE:
"After another curate's egg of a performance, he, we, and probably Hodgson are none the wiser as to whether he will be in the team this time."
Glenn Moore; Michael Carrick Gives Steven Gerrard the Freedom to Roam; The Independent (London, UK); Oct 16, 2013.