The most common and most likely answer to this crossword clue is the 8 letter word EMOTICON
E
M
O
T
I
C
O
N
More clues leading to the result EMOTICON
- Mysterious notice inscribed with second digital symbol
- One book about hoax email content?
- Book about one double-cross for Smiley?
- One might be smiling, feeling cold inside
- Number a hundred I book up for a wink or a kiss, say?
- Smiley’s People’s last chapter something not still around
- Poet penning chapter on the end of George Smiley?
- Them old books? I study something on the computer!
- Economist planned to ignore small figure on screen
- Expressive characters boosted bestselling book perhaps after chapter inserted
Buddy explains!

The straight part
We know that "Facial expression" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case facial expression = emoticon.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 EMOTICON mean?
EMOTICON noun- A graphical representation of a particular emotion of the writer, used especially in SMS, email, or other electronic communication.