Why was "Absolute Izhar" given this name?

Izhar Mutlaq (absolute clear pronunciation) is the clear pronunciation of the silent noon before the letters waw and ya within a single word. It occurs in the Qur’an in four words: Sinwan, Qinwan, Bunyan, and Ad-Dunya. It is called "absolute" because it is not restricted by the lips or throat. The reason for clearly pronouncing the noon in these words is to preserve the clarity of the meaning, for if the noon were assimilated into the ya or waw, it would resemble a doubled letter, which might obscure the meaning.