A "curate's egg" is something partly bad, partly good. In its original usage, it referred to something that is obviously and entirely bad, but is described out of politeness as nonetheless having good features that redeem it. This meaning has been largely supplanted by its less ironic modern usage, which refers to something that is in fact an indeterminate mix of good and bad, possibly with a preponderance of bad qualities.
The expression is pre-dated by an anecdote in Our Bishops and Deans (1875) by Rev. F. Arnold, referenced in an issue of The Academy: A Weekly Review of Literature, Science, and Art: "Without pledging our credence, we could afford a grin to the story of the 'young Levite' who at a bishop's breakfast-table, was so 'umble as to decline the replacement of a bad egg by a good one with a 'No thank you, my Lord, it's good enough for me'."
In May 1895, the satirical British magazine Judy published a cartoon by an artist named Wilkerson, showing a timid curate and a fierce-looking bishop at breakfast in the bishop's house. The bishop says, "Dear me, I'm afraid your egg's not good!" The curate, desperate not to offend his host and superior, replies, "Oh, yes, my Lord, really – er – some parts of it are very good." 
In November 1895, the magazine Punch (which had a much wider circulation than Judy) published a similar cartoon by staff illustrator George du Maurier. Titled True Humility, it also pictures a timid-looking curate eating breakfast with his bishop, though in this case with others at the table and servants shown in the background. The bishop says: "I'm afraid you've got a bad egg, Mr Jones." The curate replies: "Oh no, my Lord, I assure you! Parts of it are excellent!" An editor at Judy accused Punch of plagiarism, saying in an editorial, "anyone can see the coincidence for themselves". This version of the gag has become the best known.
Examples of usage
The following are some examples of the usage of the term "curate's egg":
- "The past spring and summer season has seen much fluctuation. Like the curate's egg, it has been excellent in parts." 
- "All the same it is a curate's egg of a book. While the whole may be somewhat stale and addled, it would be unfair not to acknowledge the merits of some of its parts."
- "Like the curate's egg, the details of Wegener's hypothesis were good in parts."
- "Fishman... attempted a 'systematization' of SWH [Sapir-Whorf Hypothesis], suggesting that its extreme versions were untenable..., but that, like the curate's egg, it was excellent in parts."
- "The copper network is undoubtedly very good in parts, very poor in parts, and probably very adequate for most of it. But it is like any linear network: it will have good bits and bad bits... It's like the Curate's egg; it's good in parts." (Malcolm Turnbull, Australia Federal Communications Minister describing the state of the Telstra copper telecommunications network in 2015).
- "The commanding Rencher was rated a major plus in a curate's egg of a ballet".
- "The 14 February piece by James Mugg and Andrew Davies was like the curate’s egg: good in parts." 
- Paraphrase of definition in Collins Dictionary of the English Language, London, 1986, p.381
- Oxford Dictionaries definition
- The Phrase Finder: Curate's egg
- "curate's egg Meaning in the Cambridge English Dictionary". dictionary.cambridge.org. Retrieved 2018-08-26.
- "The Curate's Egg: Parts of It Are Excellent". Quote Investigator. Retrieved 2019-03-05.
- The Academy. London: Robert Scott Walker. 1875. pp. 651–652.
- The New Oxford Dictionary of English. Oxford University Press. 1998. p. 449.
- van den Bergh, Hubert (2013). How to Sound Really Clever: 600 Words You Need to Know. A & C Black. p. 39. ISBN 1408194856.
- Nicholson, Bob (2018-07-04). "Tweet depicting 1992 Punch redrawing of the cartoon". Victorian Humour. Edge Hill University/British Library. Retrieved 2019-04-19.
Punch returned to its famous curate's egg cartoon in 1992 for the magazine's final issue, with a subversive re-telling that highlighted the apparent death of Victorian manners.
- Minister's Gazette of Fashion, 1905.
- Oxford Magazine, 1962.
- John Gribbin, The Scientists, 2001.
- Philip K. Bock, "World view and language", in Encyclopedia of Linguistics, ed. William Bright, vol. 4, Oxford University Press, 1992, p. 250.
- big, risky project’: Turnbull says NBN cost will be settled soon. Crikey.com.au (2015-08-25). Retrieved on 2015-08-25.
- Antony Tudor's Shadowplay, 1967.
- Anonymous, "Derek Rencher, Ballet Dancer," obituary, Daily Telegraph (London), 11 February 2015.
- "Unmanned naval aviation—bigger isn’t always better" at The Strategist