The most common and most likely answer to this crossword clue is the 12 letter word DOWN-AT-HEEL
I've seen this crossword clue in Financial Times
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More clues leading to the result DOWN-AT-HEEL
Buddy explains!
The straight part
We know that "Shabbily dressed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shabbily dressed = down-at-heel.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.
What does DOWN-AT-HEEL mean?
DOWN-AT-HEEL adjective- (of footwear, hyphenated when used attributively) In poor condition, especially due to having worn heels; worn-out, shabby.
- (by extension, hyphenated when used attributively) Shabbily dressed, slovenly; impoverished; shabby, dilapidated.