adj.
      - with opposite sides or surfaces relatively far apart. 
▸(of a garment or similar item) made of heavy material.
 - made up of a large number of things or people close together. 
▸
(thick with)
 densely filled or covered with.
 ▸(of the air or atmosphere, or a substance in the air) opaque, heavy, or dense:
 thick fog.
 - (of a liquid or a semi-liquid substance) relatively firm in consistency; not flowing freely.
 - informal of low intelligence; stupid.
 - (of a voice) hoarse or husky. 
▸(of an accent) very marked and difficult to understand.
 - informal having a very close, friendly relationship.
 
n.
 
(
the thick)
 the middle or the busiest part of something:
 in the thick of battle.
adv.
 thickly:
 bread spread thick with butter.
 
  Phrase
  
    - be thick on the ground
 see ground1.  - a bit thick
 Brit. informal unfair or unreasonable.  - give someone 
(or get)
 a thick ear
 Brit. informal punish someone (or be punished) with a blow on the ear.  - have a thick skin
 see skin.  - thick and fast
 rapidly and in great numbers.  - 
(as)
 thick as thieves
 informal very close or friendly.  - 
(as)
 thick as two 
(short)
 planks 
(or as a plank)
 Brit. informal very stupid.  - through thick and thin
 under all circumstances, no matter how difficult. 
   
  Derivative
  
    - thickish adj.
  - thickly adv.
 
   
  Etymology
  OE thicce, of Gmc origin.