An idiomatic expression meaning insufficient finishing touches or preparation, causing mistakes or failure at the final stage.
プレゼン自体は良かったが、詰めが甘くて質問に答えられなかった。
The presentation itself was good, but because the final preparation was lacking I couldn't answer the questions.
試合は勝てたが、詰めが甘く反省点が多い。
We won the match, but the sloppy finishing left a lot to be improved.
契約書のチェックを怠ると、詰めが甘いと言われるよ。
If you neglect to check the contract, people will say you were careless in the final details.