Sentence:  Not through fear of disobeying orders , as Eichmann kept trying to explain , but through a peculiar giddiness that began in a half acceptance of the vicious absurdities contained in the Nazi interpretation of history and grew with each of Hitler 's victories into a permanent <WSD>light</WSD> mindedness and sense of magical rightness that was able to respond to any proposal , and the more outrageous the better , `` Well , let 's try it '' . 
Meaning of the word marked with <WSD> tags:  inappropriate levity