A very small margin or narrow difference (often used for scores, votes, or competition results).
試合は僅差で幕を閉じ、観客はどちらが勝ったか分からなかった。
The match ended with a narrow margin; the spectators couldn't tell who had won.
選挙は僅差で決着し、再集計が行われた。
The election was decided by a slim margin, and a recount was carried out.
合格点との差は僅差だったが、今回は不合格になった。
The difference from the passing score was slight, but this time I failed.