imp vs waif

imp

verb
  • To provide (someone or something) with wings, hence enabling them or it to soar. 

  • To add to or unite a object with (something) to lengthen the latter out or repair it; to eke out, enlarge, strengthen. 

  • To engraft (a feather) on to a broken feather in a bird's wing or tail to repair it; to engraft (feathers) on to a bird, or a bird's wing or tail. 

noun
  • A small, mischievous sprite or a malevolent supernatural creature, somewhat comparable to a demon but smaller and less powerful, formerly regarded as the child of the devil or a demon (see sense 3.2). 

  • A mischievous child. 

  • A baby Tasmanian devil. 

waif

verb
  • To cast aside or reject, and thus make a waif. 

noun
  • A plant introduced in a place outside its native range but is not persistently naturalized. 

  • A person (especially a child) who is homeless and without means of support; also, a person excluded from society; an outcast. 

  • A very thin person. 

  • Something found, especially if without an owner; something which comes along, as it were, by chance. 

  • A small flag used as a signal. 

  • Something (such as clouds or smoke) carried aloft by the wind. 

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