The most common and most likely answer to this crossword clue is the 5 letter word SLACK
I've seen this crossword clue in The Daily Telegraph
S
L
A
C
K
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 SLACK mean?
SLACK noun- The part of anything that hangs loose, having no strain upon it.
- A tidal marsh or shallow that periodically fills and drains.
- (normally said of a rope) Lax; not tense; not firmly extended.
- Weak; not holding fast.
- Lacking diligence or care; not earnest or eager.
- Not active,successful, or violent.
- Excess; surplus to requirements.
- Vulgar; sexually explicit, especially in dancehall music.
- Slackly.
- To slacken.
- To mitigate; to reduce the strength of.
- To lose cohesion or solidity by a chemical combination with water; to slake.
- A temporary speed restriction where track maintenance or engineering work is being carried out at a particular place.
- A valley, or small, shallow dell.
- Small coal; coal dust.