The most common and most likely answer to this crossword clue is the 8 letter word GALOSHES
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More clues leading to the result GALOSHES
Buddy explains!

The straight part
We know that "overshoes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case overshoes = galoshes.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 GALOSHES mean?
GALOSHES noun- A waterproof overshoe used to provide protection from rain or snow.
- A waterproof rubber boot, intended to be worn in wet or muddy conditions.
- A clog or patten.
- Hence, an overshoe worn in wet weather.
- A gaiter, or legging, covering the upper part of the shoe and part of the leg.