niがすgasu
1.

To allow something that was previously captured or contained to become free, often by removing restraints or barriers, enabling it to escape or move independently.

2.

To fail to apprehend or capture something when it was within one's reach, resulting in a missed opportunity or loss.

3.

To discreetly facilitate the departure of someone or something, often in a way that evades detection or pursuit.

Example:

こんなにすばらしい機会を逃がしてはいけない。

toriniがすgasutoriにがnigasu
1.

To fail to secure something that was nearly captured, often due to a mistake or oversight, resulting in its escape.

2.

To inadvertently allow something that was previously within one’s control to elude capture or grasp, thus losing the opportunity.

3.

To miss the chance to obtain or hold onto something valuable, often after coming close to achieving it but ultimately being unsuccessful.