Cryptic crossword clue
Left also goes ahead and fights manual workers’ cases

The most common and most likely answer to this crossword clue is the 9 letter word TOOLBOXES

I've seen this crossword clue in The Guardian
T
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Buddy explains!

The straight part
We know that "manual workers’ cases" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case manual workers’ cases = toolboxes.
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 TOOLBOXES mean?

TOOLBOXES noun
  1. A storage case for tools.
  2. A set of pre-existing routines for use in writing new programs.
  3. Dumbass or idiot.

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