a bad egg

a bad egg

A dishonest or ill-behaved person. Primarily heard in US. We could tell he was a bad egg even at a young age.
See also: bad, egg

bad egg

An individual who turns out to be rotten, as in You can't trust him-he's simply a bad egg. Although egg had been used for various kinds of person (young, good, bad) since Shakespeare's day, this transfer of a seemingly wholesome food that, when opened, turns out to be rotten took place only in the mid-1800s. An early definition appeared in The Atheneum of 1864: "A bad egg ... a fellow who had not proved to be as good as his promise." In contrast, the schoolyard saying Last one in is a rotten egg does not have any special significance other than as a way of urging others to join an activity, jump in the water, or the like. Also see good egg.
See also: bad, egg

bad egg

n. a repellent person. You’re not such a bad egg after all.
See also: bad, egg
References in classic literature ?
I observed the doctor sniffing and sniffing, like someone tasting a bad egg.
Whin a bad egg is shut av the Army, he sings the Divil's Mass for a good riddance; an' that manes swearin' at ivrything from the Commandher-in-Chief down to the Room-Corp'ril, such as you niver in your days heard.