United put into shabby hotel — that's in plot outline (10)
I believe the answer is:
silhouette
'outline' is the definition.
(I know that silhouette is a type of outline)
'united put into shabby hotel that's in plot' is the wordplay.
'united put' becomes 'u' (I can't justify this - if you can you should give a lot more credence to this answer).
'into' means one lot of letters goes inside another.
'shabby' indicates anagramming the letters.
'that's in' means one lot of letters goes inside another.
'plot' becomes 'site' (as in a plot of land).
'hotel' is an anagram of 'lhoet'.
'u' placed within 'lhoet' is 'lhouet'.
'lhouet' inserted within 'site' is 'SILHOUETTE'.
Can you help me to learn more?
(Other definitions for silhouette that I've seen before include "Shadowy outline" , "Profile of characters" , "Outline figure" , "Outline representation" , "image" .)