Definition of "wind-egg" [wind-egg]

• An infecund or otherwise imperfect egg, as one which will produce nothing but wind (gas); a soft-shelled egg, such as may be laid by a hen that is comparatively old or has been injured. (noun)

The Century Dictionary (Public Domain)

• "And now, let us examine together this conception of yours, and see whether it is a true birth or a mere wind-egg: — You say that knowledge is perception?"
• "And I hope that I may at last help to bring your own opinion into the light of day: when this has been accomplished, then we will determine whether what you have brought forth is only a wind-egg or a real and genuine birth."
• "And now that he is born, we must run round the hearth with him, and see whether he is worth rearing, or is only a wind-egg and a sham."