The most common and most likely answer to this crossword clue is the 5 letter word TEXEL
T
E
X
E
L
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The straight part
We know that "source of wool" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case source of wool = texel.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 TEXEL mean?
TEXEL noun- An image representing the smallest unit of a texture that may be repeated to tile a region of the display.