n.
 a short, sharp sound as of two hard objects coming smartly into contact. 
▸a speech sound produced by sudden withdrawal of the tongue from the soft palate, front teeth, or back teeth and hard palate, occurring in some southern African and other languages.
 ▸Computing  an act of pressing one of the buttons on a mouse.
v.
  - make or cause to make a click. 
▸Computing  press (one of the buttons on a mouse).
 - informal become suddenly clear and understandable. 
▸become friends or be compatible from the outset.
 
 
  Derivative
  
    - clickable adj.
  - clicker n.
  - clicky adj.
 
   
  Etymology
  C16 (as v.): imitative.