The most common and most likely answer to this crossword clue is the 6 plus 2 plus 5 letter word FIGURE OF EIGHT
I've seen this crossword clue in The Times
F
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G
U
R
E
O
F
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T
Buddy explains!
The straight part
We know that "cut by blade?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cut by blade? = figure of eight.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 FIGURE OF EIGHT mean?
FIGURE OF EIGHT noun- The shape or form of an 8 (eight).
- A device for abseiling, so-called for its shape.
- A type of knot.
- (attributive) in the shape of an 8 (eight)