The most common and most likely answer to this crossword clue is the 13 letter word COMPLIMENTARY
I've seen this crossword clue in Financial Times
C
O
M
P
L
I
M
E
N
T
A
R
Y
More clues leading to the result COMPLIMENTARY
- Like free tickets - reciprocal, by the sound of it
- Free school meal tiny? Rashford’s first to get involved
- Eulogistic report comprising place north of Italy
- Describing John Dryden, maybe, critical notes given free
- Analysis about odd parts of poll is free
- Free burst lip for cutting remark
- Free permit only came about without sweetheart once
Buddy explains!

The straight part
We know that "Eulogistic" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case eulogistic = complimentary.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 COMPLIMENTARY mean?
COMPLIMENTARY adjective- In the nature of a compliment.
- Free; provided at no charge.
- With respect to the closing of a letter, formal and professional.