The most common and most likely answer to this crossword clue is the 5 letter word SCHMO
I've seen this crossword clue in The Guardian
S
C
H
M
O
More clues leading to the result SCHMO
- Fool in school system
- Mark given after school — zilch for numskull
- Fool school doctor
- Dullard ignoring odds in form checks up
- Fool Louis Armstrong forgetting a finale for trumpet!
- Leak from speech by flash jerk
- Clumsy person Louis Armstrong shunned one time
- Jerk with South Carolina medical-insurance plan
- School mom dumps married idiot in New York
- Idiot over the pond making chit-chat half-cut
Buddy explains!

The straight part
We know that "idiot in New York" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case idiot in new york = schmo.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 SCHMO mean?
SCHMO noun- A stupid or obnoxious person.