raise a hand to one's forehead in deference when meeting a person of higher social rank（对社会地位高者）举手至额致敬
柯林斯高阶英汉双解学习词典释义
N-COUNT
额发
A forelock is a piece of hair that falls over your forehead. People often used to pull their forelocks to show respect for other people of a higher class than they were.
If you say that a person tugs their forelock to another person, you are criticizing them for showing too much respect to the second person or being unnecessarily worried about their opinions.
英英词典释义
Noun
1. a lock of hair growing (or falling) over the forehead
2. a lock of a horse's mane that grows forward between the ears