Bug concealed in academic robes (7)
I believe the answer is:
microbe
'bug' is the definition.
(I know that bug can be written as microbe)
'concealed in academic robes' is the wordplay.
'concealed in' indicates a hidden word.
'MICROBE' can be found hidden inside 'academic robes'.
(Other definitions for microbe that I've seen before include "Bacterium, for example" , "Eg, bacterium" , "Bacillus" , "pathogen" , "source of disease?" .)