The most common and most likely answer to this crossword clue is the 6 letter word DEBUNK
I've seen this crossword clue in The Daily Telegraph
D
E
B
U
N
K
More clues leading to the result DEBUNK
- Edges of double bed cut down to size
- Editor standing on bed with puncture
- Show up live, making comeback to stop dip
- Ridicule half of side – rubbish
- Make a mockery of empty double bed
- According to Spooner, “Stay to dip and expose”
- Get out of bed to correct lie?
- Disparage when Head occasionally turns up with moonshine
Buddy explains!

The straight part
We know that "Make a mockery of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case make a mockery of = debunk.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 DEBUNK mean?
DEBUNK verb- To discredit, or expose to ridicule the falsehood or the exaggerated claims of something.