損じ is read as そんじ (sonji) and means slip.
そんじ
sonji
そこなう
to fail to ...
そんがい
damage
そんしつ
loss (of assets, profit, etc.)
そん
disadvantage
そんとく
loss and gain
そこねる
to miss one's chance to (do something)
そんする
to lose (money, etc.)
そんきん
financial loss
そんじる
to harm
そんしてとくとる
you must lose a fly to catch a trout
そんしてとくとれ
そんき