not exactly the same as someone or something else

Legally, a draft or non-identical copy is a separate document.

It would look better if the houses had non-identical porches but the developer uses a builder that mass-produces only a certain number of styles. 如果这些房子有不同样式的门廊看起来会更好看，但开发商使用的建筑商只批量生产有限的几种风格。

(of children born to the same mother on the same occasion) not looking exactly the same because they developed from separate eggs

It was the first successful ovarian tissue transplant between two non-identical sisters.

Doctors believe she is expecting triplets and a non-identical brother. 医生认为她怀的是三胞胎和另一个异卵男婴。