what does idhgaam noon sakeen means?

what does idhgaam noon sakeen means?
Idghaam means merging.  So when a letter has "idghaam" into another, it merges into second letter so that what is heard is the second letter, empahisized with a shaddah (double).  Noon is the Arabic letter  .  Saakinah (you wrote sakeen, but the correct word is saakinah) means voweless.  So idghaam noon saakinah means, the merging of the non-voweled letter into the letter which follows it.

For more information please see: