complexed vs over one's head

complexed

adj
  • Combined in the form of a complex 

over one's head

adj
  • More complex or confusing than one can understand; beyond one’s comprehension. 

  • Used other than figuratively or idiomatically: see over, head. 

  • More than one can handle; too much (especially in over one's head). 

  • Performing at a level greatly superior to one's usual level of performance. 

  • Directed to someone with authority over the person, so as to avoid requiring the approval of the person himself or herself. 

How often have the words complexed and over one's head occurred in a corpus of books? (source: Google Ngram Viewer )