The most common and most likely answer to this crossword clue is the 12 letter word BACCHANALIAN
B
A
C
C
H
A
N
A
L
I
A
N
More clues leading to the result BACCHANALIAN
- Drunken support a stranger talked of
- Merrymaking composer pens the ultimate in music, rejecting secure articles
- Reveller said bet on outsider
- Favour a foreigner’s pronunciation of ‘Dionysiac‘
- Support a stranger picked up involved in drunken sprees
- Stick up for a foreigner caught embracing drunken revelry
- Provide support for a foreigner reported to be drunk
- Reportedly support Martian, possibly debauched
Buddy explains!

The straight part
We know that "Dionysiac" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dionysiac = bacchanalian.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 BACCHANALIAN mean?
BACCHANALIAN noun- A bacchanal; a drunken reveler.
- Of or pertaining to the festival of Bacchus; relating to or given to reveling and drunkenness.