The most common and most likely answer to this crossword clue is the 6 plus 7 letter word WINDOW DRESSER
W
I
N
D
O
W
D
R
E
S
S
E
R
Buddy explains!
The straight part
We know that "job in department store?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case job in department store? = window dresser.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.