The most common and most likely answer to this crossword clue is the 6 letter word LEXEME
I've seen this crossword clue in Financial Times
L
E
X
E
M
E
Buddy explains!

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 LEXEME mean?
LEXEME noun- A unit of lexical meaning, roughly corresponding to the set of inflected forms taken by a single word.
- An individual instance of a continuous character sequence without spaces, used in lexical analysis (see token).