The most common and most likely answer to this crossword clue is the 7 letter word MASKING
I've seen this crossword clue in The Sunday Telegraph
M
A
S
K
I
N
G
More clues leading to the result MASKING
Buddy explains!

The straight part
We know that "Screening" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case screening = masking.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 MASKING mean?
MASKING verb- To cover (the face or something else), in order to conceal the identity or protect against injury; to cover with a mask or visor.
- To disguise; to cover; to hide.
- To conceal; also, to intervene in the line of.
- To cover or keep in check.
- To take part as a masker in a masquerade
- To wear a mask; to be disguised in any way
- To cover or shield a part of a design or picture in order to prevent reproduction or to safeguard the surface from the colors used when working with an air brush or painting
- To set or unset (certain bits, or binary digits, within a value) by means of a bitmask.
- To disable (an interrupt, etc.) by setting or unsetting the associated bit.
- To mash.
- To mix malt with hot water to yield wort.
- To be infused or steeped.
- To prepare tea in a teapot; alternative to brew.
- To bewilder; confuse.
- The act by which something is masked.
- An entertainment at which the guests conceal their faces with masks.
- The practice of wearing safety masks.