The most common and most likely answer to this crossword clue is the 7 plus 7 letter word RUDYARD KIPLING
I've seen this crossword clue in The Guardian
R
U
D
Y
A
R
D
K
I
P
L
I
N
G
More clues leading to the result RUDYARD KIPLING
Buddy explains!

The straight part
We know that "If writer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case if writer = rudyard kipling.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.