The most common and most likely answer to this crossword clue is the 2 plus 4 letter word IN VAIN
I've seen this crossword clue in The Guardian
I
N
V
A
I
N
More clues leading to the result IN VAIN
- Occupying vessel, we hear, to no avail
- Six surrounding American in pub to no avail
- One way to carry goods across India, unsuccessfully?
- Virginia and I occupying tavern to no avail
- Where nurse might put needle, reportedly to no avail?
- Popular commercial vehicle carries one to no avail
- One infiltrates at front, to no avail
- Reportedly, where injection goes will be making no difference
- Unsuccessfully leading army maybe around island
- Fruitlessly drugs may circulate here, we hear
Buddy explains!
The straight part
We know that "unsuccessfully" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unsuccessfully = in vain.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.