シツ, うしな.う, う.せる
lose, error, fault, disadvantage, loss
JLPT3 G4 S5 F447
The relevant seal inscription form is 手 hand/action indicator + a line slanting downward → (by means of beating/flogging etc.) cause a person to *slip*/lose his footing (compare 跌) → *lose* → *miss* (an opportunity) → *mistake*.
[Full Kanji Etymology List]