corroborant vs roborant

corroborant

adj
  • strengthening; supporting; corroborating 

noun
  • Anything that gives strength or support; a tonic. 

  • A piece of corroborating evidence. 

roborant

adj
  • That strengthens or energizes. 

noun
  • A restorative tonic. 

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