The most common and most likely answer to this crossword clue is the 8 letter word OBSCURED
I've seen this crossword clue in The Guardian
O
B
S
C
U
R
E
D
More clues leading to the result OBSCURED
- Former schoolfellows no longer ill? That's not made clear
- Alumni better out of sight?
- Outside broadcasts restored in secret?
- Good news about alumnus who was poorly hidden
- Headless biblical figure’s restored and shrouded
- Old bottles, emptied and preserved, hidden
- Jack, abandoning tasks, smoked behind screen
- Covert observation on copper linked to left-winger
- Former pupil’s successfully treated? That’s made unclear
- Former pupils smoked? That’s hard to see!
Buddy explains!

The straight part
We know that "behind screen" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case behind screen = obscured.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 OBSCURED mean?
OBSCURED verb- To render obscure; to darken; to make dim; to keep in the dark; to hide; to make less visible, intelligible, legible, glorious, beautiful, or illustrious.
- To hide, put out of sight etc.
- To conceal oneself; to hide.