The most common and most likely answer to this crossword clue is the 10 letter word ESPECIALLY
I've seen this crossword clue in Financial Times
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More clues leading to the result ESPECIALLY
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The straight part
We know that "Particularly" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case particularly = especially.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 ESPECIALLY mean?
ESPECIALLY adverb- (manner) In a special manner; specially.
- (focus) Particularly; to a greater extent than is normal.
- (focus) Used to place greater emphasis upon someone or something.