The most common and most likely answer to this crossword clue is the 7 letter word BARRING
I've seen this crossword clue in The Daily Telegraph
B
A
R
R
I
N
G
More clues leading to the result BARRING
Buddy explains!
The straight part
We know that "Blocking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case blocking = barring.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 BARRING mean?
BARRING verb- To obstruct the passage of (someone or something).
- To prohibit.
- To lock or bolt with a bar.
- To imprint or paint with bars, to stripe.
- (collective) Bars; an arrangement or pattern of stripes or bars.
- The act of fitting or closing something with bars.
- The exclusion of someone; blackballing.
- Timber used for supporting the roof or sides of shafts.
- The sewing of a decorative bar or tack upon a fabric or leather.
- Unless something happens; excepting; in the absence of.