The most common and most likely answer to this crossword clue is the 10 letter word DEFINITION
I've seen this crossword clue in The Times
D
E
F
I
N
I
T
I
O
N
More clues leading to the result DEFINITION
- Element of clue, one I'd fit in deviously
- Sharpness found in all of these clues
- Certain detail on which no one comes up with an explanation
- Sense economic decline with trendy Italy supplanting the French
- Meaning of sharp focus
- Do infinite exercises to get part of clue
- Note: I find I improved sharpness of image
- Dictionary entry that’s clearer when higher
Buddy explains!

The straight part
We know that "Element of clue" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case element of clue = definition.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 DEFINITION mean?
DEFINITION noun- A statement of the meaning of a word or word group or a sign or symbol (dictionary definitions).
- (usually with the definite article the) A clear instance conforming to the dictionary or textbook definition.
- A statement expressing the essential nature of something; formulation
- The action or process of defining.
- The act of defining; determination of the limits.
- A product of defining.
- The action or power of describing, explaining, or making definite and clear.
- Clarity of visual presentation, distinctness of outline or detail.
- Clarity, especially of musical sound in reproduction.
- Sharp demarcation of outlines or limits.
- The degree to which individual muscles are distinct on the body.
- A statement which provides a previous declaration with a value or body of a subroutine (in the case of function).
- A statement that establishes the referent of a term or notation.