ball touches clothing
 

The scenario: The ball is thrown by player A on team A and the ball touches the loose clothing (shorts or shirt) of player B on team B, and then goes out of bounds. The ball does not touch the body of player B, only the clothing.

Is the ball then "out" on player A with the loose clothing or player B who threw the ball?

The ball hitting the uniform or other clothing that a player is wearing counts as contacting that player. If that is the last touch before it goes out-of-bounds. It is the opponents ball.