refrain vs strain

refrain

noun
  • The chorus or burden of a song repeated at the end of each verse or stanza. 

  • A much repeated comment, complaint, or saying. 

verb
  • To stop oneself from some action or interference; to abstain. 

  • To abstain from (food or drink). 

strain

noun
  • Any sustained note or movement; a song; a distinct portion of an ode or other poem; also, the pervading note, or burden, of a song, poem, etc. 

  • The act of straining, or the state of being strained. 

  • Language that is eloquent, poetic, or otherwise heightened. 

  • An injury resulting from violent effort; a sprain. 

  • A dimensionless measure of object deformation either referring to engineering strain or true strain. 

  • A kind or sort (of person etc.). 

  • A particular variety of a microbe, virus, or other organism, usually a taxonomically infraspecific one. 

  • A violent effort; an excessive and hurtful exertion or tension, as of the muscles. 

  • Hereditary character, quality, tendency, or disposition. 

verb
  • To damage by drawing, stretching, or the exertion of force. 

  • To urge with importunity; to press. 

  • To act upon, in any way, so as to cause change of form or volume, as when bending a beam. 

  • To apply a force or forces to by stretching out. 

  • To exert or struggle (to do something), especially to stretch (one's senses, faculties etc.) beyond what is normal or comfortable. 

  • To separate solid from liquid by passing through a strainer or colander 

  • To percolate; to be filtered. 

  • To make uneasy or unnatural; to produce with apparent effort; to force; to constrain. 

  • hug somebody; to hold somebody tightly. 

  • To stretch beyond its proper limit; to do violence to, in terms of intent or meaning. 

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