The most common and most likely answer to this crossword clue is the 9 letter word LANDSLIDE
I've seen this crossword clue in The Daily Telegraph
L
A
N
D
S
L
I
D
E
More clues leading to the result LANDSLIDE
- Stupidly deal in LSD? It’s a disaster
- Dangerous movement in which Linda’s led astray
- Mortal danger: country is led astray
- Runaway victory of country team rounding lake
- Touch down before team secures 50 for decisive win
- Leader of lions died during Daniel’s unorthodox convincing victory
- Left coming into party to secure first big majority
- Obtain playground equipment to get overwhelming election victory
- The opposite of a water chute?
- Hardly what the Tories got in June, so a massive descent
Buddy explains!

The straight part
We know that "Overwhelming result" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case overwhelming result = landslide.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 LANDSLIDE mean?
LANDSLIDE noun- A natural disaster that involves the breakup and downhill flow of rock, mud, water and anything caught in the path.
- A vote won by a wide or overwhelming majority.
- To undergo a landslide.