clicker

Clicker is a term used in the games like World of Tanks or Armored Warfare.
Players use it to make fun of players who play one particular kind of vehicle namely artillery, because artillery players, in basic terms, only need to use their mouse and click to do damage.

"Artillery hits player".
Player who got hit by artillery: "You damn clicker".

Player: "Clickers have no skill"
Player: "That Clicker is so annoying"