The most common and most likely answer to this crossword clue is the 6 letter word OPAQUE
O
P
A
Q
U
E
More clues leading to the result OPAQUE
- Drop a question that, in part, is not clear
- Impenetrable work leads to awkward questions, upsetting editor
- Obscure work — a strange hesitation to avoid it
- Pop a question that’s a bit unclear
- Dark film has length cut after Oscar
- Some pop a question that’s not clear
- Hard to understand old memorial with line missing
- Stop a queen revealed to be dense
- Dull pain reported after surgery
- Unintelligible work, one somewhat lacking in appeal
Buddy explains!

The straight part
We know that "Hard to understand" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hard to understand = opaque.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 OPAQUE mean?
OPAQUE noun- An area of darkness; a place or region with no light.
- Something which is opaque rather than translucent.
- To make, render (more) opaque.
- Neither reflecting nor emitting light.
- Allowing little light to pass through, not translucent or transparent.
- Unclear, unintelligible, hard to get or explain the meaning of
- Obtuse, stupid.
- Describes a type for which higher-level callers have no knowledge of data values or their representations; all operations are carried out by the type's defined abstract operators.