The most common and most likely answer to this crossword clue is the 6 letter word INDIAN
I've seen this crossword clue in Financial Times
I
N
D
I
A
N
More clues leading to the result INDIAN
- Single chap touring North Dakota, one from Mumbai, perhaps
- Asian support hotel welcomes back
- Popular girl - an inhabitant of Bhopal, perhaps
- Fashionable girl meeting an inhabitant of Mumbai, perhaps
- National assistance needed back in local . . . .
- Restaurant in unfinished state
- Race to boost charity held in pub
- National support raised through drinks supplier
- Help rejected in pub restaurant?
- Restaurant help served up in hostelry
Buddy explains!
The straight part
We know that "National" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case national = indian.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.