The most common and most likely answer to this crossword clue is the 9 letter word SKINNIEST
I've seen this crossword clue in Financial Times
S
K
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More clues leading to the result SKINNIEST
Buddy explains!

The straight part
We know that "Most angular" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case most angular = skinniest.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 SKINNIEST mean?
SKINNIEST adjective- Thin, generally in a negative sense (as opposed to slim, which is thin in a positive sense).
- (of food or beverages) Low-fat.
- Naked; nude (chiefly used in the phrase skinny dipping).
- (of clothing) tight-fitting