The most common and most likely answer to this crossword clue is the 6 letter word WELDER
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More clues leading to the result WELDER
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The straight part
We know that "Worker who joins" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case worker who joins = welder.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 WELDER mean?
WELDER noun- One who welds, or unites pieces of iron, etc., by welding.
- One who welds, or wields.
- An item of equipment for welding with: an electric welder.
- A manager; an actual occupant; a land-tenant holding under the farmer or middleman.