The most common and most likely answer to this crossword clue is the 8 letter word BULLSHOT
B
U
L
L
S
H
O
T
Buddy explains!
The straight part
We know that "Cocktail" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cocktail = bullshot.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 BULLSHOT mean?
BULLSHOT noun- A phony screenshot created for promotional purposes.