aculeated vs lowering

aculeated

adj
  • Having a sharp point; armed with prickles. 

  • Pungent, incisive. 

lowering

adj
  • Lurking, skulking, menacing. 

  • Dark and menacing. 

  • That lowers or frowns. 

noun
  • The act of something being lowered. 

How often have the words aculeated and lowering occurred in a corpus of books? (source: Google Ngram Viewer )