slinky vs under the radar

slinky

adj
  • Of a garment: close-fitting; clingy. 

  • Furtive, stealthy or catlike. 

under the radar

prep
  • Without attracting notice; in an undetected or secretive manner. 

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