The most common and most likely answer to this crossword clue is the 5 letter word GEMMA
G
E
M
M
A
Buddy explains!
The straight part
We know that "bud" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bud = gemma.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 GEMMA mean?
GEMMA noun- A bud; an asexual reproductive structure, as found in liverworts and hydra, able to produce new individuals from a cluster of cells.