First show house architect built big, yet dilapidated in appearance (6)
I believe the answer is:
shabby
'dilapidated in appearance' is the definition.
'shabby' can be an answer for 'dilapidated' (I've seen this before). I'm unsure of the 'in appearance' bit.
'first show house architect built big yet' is the wordplay.
'first' says to take the initial letters.
The first letters of 'show house architect built big yet' is 'SHABBY'.
Can you help me to learn more?
(Other definitions for shabby that I've seen before include "Unworthy" , "Worn and run-down, like clothes" , "in worn and dirty clothes" , "Down at heel" , "Seedy and rundown" .)