awhile vs momentarily

awhile

adv
  • For some time; for a short time. 

  • In the meantime; during an implicit ongoing process. 

momentarily

adv
  • In a momentary manner; for a moment or instant. 

  • Progressively; moment by moment. 

  • In a moment or very soon; any minute now, any time now. 

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