Board Game Arena

On the game history page of a profile it lists Most Frequent Opponents. It displays them as 'X hits on Y games (Z%)'.

What are 'hits' (X)?

Amount of victories you've had against that player.

Note that this isn't the number of times you have won the game when that player is playing -- it is the number of times you have come in a higher position than them. While these numbers are the same for 2-player games, they are not the same in games with more than 2 players.