chinless wonder

noun1

1. •
   (slang, disapproving) An ineffectual upper-class man, typically dim-witted and of a weak or indecisive character, frequently one who gained his position through nepotism or social connections.

   • She is thin, starved to near perfection […] He, a chinless wonder, a credit to Carnaby Street; they stand hand in hand before the enquiry desk — 1967