The most common and most likely answer to this crossword clue is the 6 letter word WIDEST
I've seen this crossword clue in The Guardian
W
I
D
E
S
T
More clues leading to the result WIDEST
- Whiskey? That is most generous
- Broad stumped; most difficult for the wicket-keeper?
- Waffles for starter? Poor diets are most extensive
- Heading for workshop that is most spacious
- View, finally, that is most extensive
- Wicket! That is Broad, superlatively!
- Point that is most comprehensive
- No, no. Now tide’s out it’s most extensive
- End of meadow that is most spread out
- Top of wall that is hardest to jump over?
Buddy explains!

The straight part
We know that "most extensive/most extensive" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case most extensive/most extensive = widest.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 WIDEST mean?
WIDEST adjective- Having a large physical extent from side to side.
- Large in scope.
- Operating at the side of the playing area.
- On one side or the other of the mark; too far sideways from the mark, the wicket, the batsman, etc.
- Made, as a vowel, with a less tense, and more open and relaxed, condition of the organs in the mouth.
- (now rare) Vast, great in extent, extensive.
- Located some distance away; distant, far.
- Far from truth, propriety, necessity, etc.
- Of or supporting a greater range of text characters than can fit into the traditional 8-bit representation.