Formal body (5)
I believe the answer is:
stiff
This clue is a double definition.
'formal' is the first definition.
(similar in meaning)
'body' is the second definition.
(I know that body can be written as stiff)
(Other definitions for stiff that I've seen before include "cheat" , "Rigid, unbending" , "Frigid" , "Inflexible" , "Starched, rigid" .)