halfhearted
Done without real effort, energy, or enthusiasm.
Halfhearted means doing something without real enthusiasm or effort, as if only half of your heart is in it. When you make a halfhearted attempt to clean your room, you might shove things under the bed instead of actually organizing. When someone offers a halfhearted apology, you can tell they don't really mean it because their voice is flat and they won't look you in the eye.
The word captures that feeling of going through the motions without genuine commitment. A halfhearted compliment sounds forced and insincere. A halfhearted cheer from the crowd tells the team that the fans have given up.
Think about the difference between studying hard for a test and just skimming the material for five minutes before bed. That's the gap between wholehearted effort and halfhearted effort. When you approach something halfheartedly, you usually end up with mediocre results because you never gave it your full energy or attention. The opposite is wholehearted: putting your complete focus and enthusiasm into what you're doing.