Perplexity is a feeling of being confused and frustrated because you do not understand something. He began counting them and then, with growing perplexity, counted them a second time
The quality or state of being perplexed or puzzled; complication; intricacy; entanglement; distraction of mind through doubt or difficulty; embarrassment; bewilderment; doubt
The perplexities of something are those things about it which are difficult to understand because they are complicated. the perplexities of quantum mechanics