"Both in English and in German the idea 'deaf' is applied to 'a nut without a kernel,' — a deaf nut, eine taube Nuss. De Quincey (Autob. Sketches, I, p. 91) speaks of 'what children call a deaf nut, offering no kernel;' and Bishop Hall, in the seventeenth century, uses this phrase of 'a man that hath outward service without inward fear.' In English and German dialects, and sometimes in the literary forms of these tongues, the term 'deaf' is given to empty ears of corn, light grain, things that are hollow, empty, barren, unproductive, weak, insipid, etc., particularly land, eggs, etc. Murray's great English dictionary, Wright's English Dialect dictionary and Grimm's German dictionary contain a mass of evidence on these points."
https://archive.org/stream/jstor-1412229/1412229_djvu.txtOld-fashioned, though, I suppose.