Nonequivalent and Noninterchangeable

Nonequivalent adjective - Not equal or interchangeable in value, quantity, or significance.

Noninterchangeable and nonequivalent are semantically related. In some cases you can use "Noninterchangeable" instead an adjective "Nonequivalent".

Noninterchangeable adjective - Such that the terms of an expression cannot be interchanged without changing the meaning.

Nonequivalent and noninterchangeable are semantically related. You can use "Nonequivalent" instead an adjective "Noninterchangeable".