The most common and most likely answer to this crossword clue is the 9 letter word REACHABLE
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More clues leading to the result REACHABLE
Buddy explains!

The straight part
We know that "accessible" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case accessible = reachable.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 REACHABLE mean?
REACHABLE noun- Someone or something that can be reached.
- Within easy reach; accessible
- (of a node) That may be reached from another node in a graph by passing along one or more lines