Cryptic crossword clue
Clearing one barrel — gallons going after late drinking session 10

The most common and most likely answer to this crossword clue is the 10 letter word UNBLOCKING

I've seen this crossword clue in The Guardian
U
N
B
L
O
C
K
I
N
G

Buddy explains!

The straight part
We know that "Clearing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case clearing = unblocking.
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 UNBLOCKING mean?

UNBLOCKING verb
  1. To remove or clear a block or obstruction from.
  2. To free or make available.
  3. In whist, to throw away a high card so as not to interrupt one's partner's long suit.
UNBLOCKING noun
  1. The process by which something is unblocked.

Latest crossword clues with full explanations