The most common and most likely answer to this crossword clue is the 7 plus 6 letter word SISTINE CHAPEL
S
I
S
T
I
N
E
C
H
A
P
E
L
More clues leading to the result SISTINE CHAPEL
- Church in Palestine is remarkable place of worship
- Cheap tinsel is out of place in this sacred building
- Relative, male, scoring point at the Spanish religious building
- See great work on ceiling here: it’s nice, complicated in form, and large
- Pestilence has broken out in part of the Vatican
- Painter’s masterpiece, else his paint misplaced around ceiling, primarily
- See great work on ceiling here: it's nice, complicated in form, and large
Buddy explains!

The straight part
We know that "Painter’s masterpiece" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case painter’s masterpiece = sistine chapel.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.