in the groove vs rare

in the groove

prep
  • Running or performing extremely smoothly, especially (music, slang) playing perfectly, perfectly in sync with others, or with perfect focus. 

  • Used other than figuratively or idiomatically: see in, groove. 

rare

verb
  • To rear, bring up, raise. 

  • To rear, rise up, start backwards. 

adj
  • Thin; of low density. 

  • Very uncommon; scarce. 

  • Particularly of meat, especially beefsteak: cooked very lightly, so the meat is still red. 

  • Good; enjoyable. 

noun
  • A scarce or uncommon item. 

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