ورد شطر العقد
Rejection of a portion of a contractual act.
Where a contract requires complementary components, the presence of one component is insufficient. Rejection of the other necessary component prevents the complete legal transaction from being established.
For illustration, an offer without legally effective acceptance does not complete a bilateral contract. The source says shaṭr al-ʿaqd (a part of the contract), not sharṭ al-ʿaqd (a condition of the contract); confusing these two words would change the teaching point.