The most common and most likely answer to this crossword clue is the 10 letter word ELLIPTICAL
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Buddy explains!

The straight part
We know that "Like nothing/obscure" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case like nothing/obscure = elliptical.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 ELLIPTICAL mean?
ELLIPTICAL noun- An elliptical galaxy.
- An elliptical trainer.
- In a shape of, or reminding of, an ellipse; oval.
- Of, or showing ellipsis; having a word or words omitted.
- (of speech) Concise, condensed.
- Elliptic.