Today's word is brought to you by lindahoyland--many thanks :)
~~~
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.

(from Wikipedia, you can read more in this article)