The most common and most likely answer to this crossword clue is the 7 letter word GRIMACE
I've seen this crossword clue in Independent
G
R
I
M
A
C
E
More clues leading to the result GRIMACE
- Smirk, as I’m in a sin-free state
- Stern fighter pilot's facial distortion
- Expression of good fighter pilot on edge?
- Sneer, maybe, from British king, a symbol of authority
- Wry expression from serious expert
- Painful expression I am to write into prayer
- Expression of pilot faced with emergency?
- Scowl in dreadful shot
- In elegance, Mudd is lower
- Lower margin stops goodservice
Buddy explains!

The straight part
We know that "Lower" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lower = grimace.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 GRIMACE mean?
GRIMACE noun- A contorted facial expression, often expressing contempt or pain.
- Affectation, pretence.
- To make grimaces; to distort one's face; to make faces.