English Idioms and Idiomatic Expressions 

HAIR

Idioms relating to the hair  
from:  'bad hair day'   to:  'widow's peak'

• bad hair day
  • Originating as a humorous comment about one's hair being unmanageable, this term has broadened to mean a day when everything seems to go wrong.
    "What's wrong with Jenny? Is she having a bad hair day?"
    
    
• hair of the dog
  • Using as a remedy a small amount of what made you ill, for example a drop of alcohol when recovering from drinking too much, is called 'a hair of the dog that bit you'.
    "Here, have a drop of this. It's a hair of the dog that bit you!"
    
    
• by a hair's breadth
  • If you avoid or miss something by a hair's breadth, you only just manage to escape from a danger.
    "A slate fell off the roof and missed the child by a hair's breadth."
    
    
• get in someone's hair
  • If you are getting in someone's hair, you are annoying them so much that they can't get on with what they are doing.
    "I'd finish the report more quickly if my colleague wasn't getting in my hair all the time."
    
    
• let your hair down
  • If you suggest that someone should let their hair down, you are telling them to relax and enjoy themselves.
    "Come on! We're not in the office now. You can let your hair down!"
    
    
• makes your hair stand on end
  • If you are absolutely terrified of something, it makes your hair stand on end.
    "Just the thought of getting on a plane makes my hair stand on end!"
    
    
• (not/never) a hair out of place
  • If someone does not have a hair out of place, their appearance is perfect.
    "Angela is always impeccably dressed - never a hair out of place."
    
    
• tear one's hair out
  • If someone is tearing their hair out, they are extremely agitated or distressed about something.
    "I've been tearing my hair out all morning trying to find the error."
    
    
• (not) turn a hair
  • If someone does not turn a hair, they show no emotion in circumstances where a reaction is expected.
    "When the police came to arrest him, he didn't turn a hair."
    
    
• split hairs
  • If you split hairs, you pay too much attention to differences that are very small or unimportant.
    "If we start splitting hairs, we'll never reach an agreement!"
    
    
• widow's peak
  • A V-shaped point formed by the hair in the centre of the forehead is called a widow's peak.
    (It was believed to be a sign of early widowhood.)