The most common and most likely answer to this crossword clue is the 5 letter word SPEAK
I've seen this crossword clue in The Daily Telegraph
S
P
E
A
K
More clues leading to the result SPEAK
Buddy explains!

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 SPEAK mean?
SPEAK noun- A low class bar, a speakeasy.
- Language, jargon, or terminology used uniquely in a particular environment or group.
- Speech, conversation.
- To communicate with one's voice, to say words out loud.
- To have a conversation.
- (by extension) To communicate or converse by some means other than orally, such as writing or facial expressions.
- To deliver a message to a group; to deliver a speech.
- To be able to communicate in a language.
- To utter.
- To communicate (some fact or feeling); to bespeak, to indicate.
- (sometimes humorous) To understand (as though it were a language).
- To produce a sound; to sound.
- Of a bird, to be able to vocally reproduce words or phrases from a human language.
- To address; to accost; to speak to.