Stiff and formal (7)
I believe the answer is:
starchy
'stiff and formal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for starchy that I've seen before include "Stiff and formalistic" , "Stiff, like potatoes" , "Conventional" , "Unbending" , "Stiff, formal" .)