good egg, a

Someone who is known to be trustworthy and kind. Joey's a good egg. He always makes time to help others in need.

Fig. a good and dependable person. He seems like a good egg. I'll take a chance on him.

Also, a good scout. An amiable, basically nice person. For example, You can always count on her to help; she's a good egg, or His friends all think Dad's really a good scout. This colloquial antonym of bad egg dates from the early 1900s, as did the variant.

If you describe someone as a good egg, you mean that they are a kind and reliable person. Her father's a bit bad-tempered, but basically a good egg.

An agreeable, trustworthy person. This slangy expression has outlived bad egg, which it actually implied in the sixteenth century. “Neither good egge nor good bird,” went the saying, meaning the young (egg) would not turn into praiseworthy adults (bird). In the nineteenth century this continued to be spelled out: “A bad egg [is] a fellow who has not proved to be as good as his promise” (The Athenaeum, 1864). The favorable aspect of good egg dates from the early twentieth century. Rudyard Kipling used it in Traffics and Discoveries (1904): “‘Good egg!’ quoth Moorshed.”

An agreeable, helpful person. The phrase applied to someone of value in terms of utility, the opposite of a no-good rotten egg. It was most often heard in such requests as “Be a good egg and mail this letter for me” or “Pour me another whisky, like a good egg.”