The most common and most likely answer to this crossword clue is the 10 letter word FRUSTRATES
I've seen this crossword clue in Financial Times
F
R
U
S
T
R
A
T
E
S
More clues leading to the result FRUSTRATES
Buddy explains!

The straight part
We know that "blocks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case blocks = frustrates.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 FRUSTRATES mean?
FRUSTRATES verb- To disappoint or defeat; to vex by depriving of something expected or desired.
- To hinder or thwart.
- To cause stress or annoyance.