<unk>  is a psychological phenomenon in which repetition causes a word or phrase to temporarily lose meaning for the listener, who then perceives the speech as repeated meaningless sounds. Extended inspection or analysis (staring at the word or phrase for a lengthy period of time) in place of repetition also produces the same effect.
Semantic satiation
Derealization
Automatism 
Body substance isolation
Mood congruence
Combat stress reaction
Sexual anhedonia
Premonitory urge