The most common and most likely answer to this crossword clue is the 5 letter word JOLLY
I've seen this crossword clue in The Daily Telegraph
J
O
L
L
Y
More clues leading to the result JOLLY
Buddy explains!

The straight part
We know that "Very/merry" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very/merry = jolly.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 JOLLY mean?
JOLLY noun- A pleasure trip or excursion.
- A marine in the English navy.
- To amuse or divert.
- Full of merriment and high spirits; jovial.
- Full of life and mirth; jouous; merry.
- Splendid, excellent, pleasant
- Large
- Very, extremely