Seemliness (7)
I believe the answer is:
decorum
'seemliness' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for decorum that I've seen before include "Dignity of behaviour or proceedings" , "This is becoming" , "Seemly behaviour" , "Proper behaviour; etiquette" , "(Of outward appearances) what is proper" .)