The most common and most likely answer to this crossword clue is the 12 letter word RESPECTIVELY
I've seen this crossword clue in The Daily Telegraph
R
E
S
P
E
C
T
I
V
E
L
Y
Buddy explains!
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 = respectively.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 RESPECTIVELY mean?
RESPECTIVELY adverb- In a relative manner; often used when comparing lists, where the term denotes that the items in the lists correspond to each other in the order they are given.