The most common and most likely answer to this crossword clue is the 11 letter word COGNOSCENTI
I've seen this crossword clue in The Daily Telegraph
C
O
G
N
O
S
C
E
N
T
I
More clues leading to the result COGNOSCENTI
- Lack of fragrance disturbing fellow soldier in Buffs?
- Informed experts caught in dreadful congestion
- Niff after cocking leg occupies heartless dog experts
- Connoisseurs cooing drunkenly about bouquet
- Those who know iodine component has no odour at first
- Finally, traffic congestion gets fixed by the authorities
- Connoisseurs, one hundred with terrible congestion
- Those in the know since con got busted
Buddy explains!

The straight part
We know that "Connoisseurs" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case connoisseurs = cognoscenti.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 COGNOSCENTI mean?
COGNOSCENTI noun- Someone possessing superior or specialized knowledge in a particular field; a connoisseur.