English Idioms and Idiomatic Expressions 

COMPARISONS - SIMILARITY, page 3

Idioms relating to comparisons and similarities
from:  'as quick as a dog can lick a dish'   to:  'as tough as old boots'

• as quick as a dog can lick a dish
  • If you do something surprisingly fast, you do it as quick as a dog can lick a dish.
    "He packed his bag as quick as a dog can lick a dish."
    
    
• as quiet as a mouse
  • When someone is as quiet as a mouse, they make no noise at all.
    "The burglar was as quiet as a mouse as he moved around the house."
    
    
• as scarce as hens' teeth
  • To say that something is as scarce as hens' teeth emphasizes that it is extremely rare, to the point of non-existence.
    "Take enough supplies. Water is as scarce as hens' teeth where you're going!"
    
    
• as sharp as a tack
  • A person who is as sharp as a tack is able to think quickly and learn very fast.
    "You won't have to explain it to him twice. He's as sharp as a tack."
    
    
• as slippery as an eel
  • To say that someone is as slippery as an eel means that they are difficult to catch and they manage to avoid answering questions.
    "The man was as slippery as an eel. He was arrested for theft several times but was never convicted."
    
    
• as sly as a fox
  • Someone who is as sly as a fox is cunning and clever at getting what they want, especially by deceiving or tricking people.
    "Be wary of that insurance salesman. He's as sly as a fox."
    
    
• (as) straight as an arrow
  • Someone who is as straight as an arrow is a morally upright person who is extremely honest.
    "You can leave the keys with Andy. He's as straight as an arrow."
    
    
• (as) straight as a ramrod
  • Someone who is (as) straight as a ramrod is a person who keeps a straight back and looks very serious.
    "When my grandfather invited us for dinner, he used to sit straight as a ramrod at the head of the table."
    
    
• as thick as thieves
  • To say that two people are as thick as thieves means that they are very close friends who are very loyal to each other.
    "Chris always takes Danny's side. They're as thick as thieves."
    
    
• as stubborn as a mule
  • If someone is as stubborn as a mule, they are very obstinate and unwilling to listen to reason or change their mind.
    "His friends advised him to accept the offer, but you know Larry - he's as stubborn as a mule!"
    
    
• as tough as old boots
  • If something, specially meat, is (as) tough as old boots, it is hard to cut and difficult to chew.
    (This can also refer to a person who is strong either physically or in character.)
    "I was served a steak as tough as old boots."