Wiktionary
empty suit
n. A person ineffective or incompetent in his/her position of authority. Derived from unfavorable observations that ineffective professionals are memorable only for what they wear and not what they accomplish at the workplace. [c. 1970]
Usage examples of "empty suit".
There was also the empty suit of armor of an armadillo, a stuffed dodo, and the long spiral tusk of a narwhal, playfully labeled by Skip, Unicorn Horn.
Belazir ignored him, diving for the empty suit that followed behind the warrior.
The man seemed ready to weep with relief Belazir ignored him, diving for the empty suit that followed behind the warrior.
I took Singer's shoulders and Doc took his feet, and we carefully laid him out at the feet of the empty suit.