circumlocution vs euphemism

circumlocution

noun
  • Unnecessary use of extra words to express an idea, such as a pleonastic phrase (sometimes driven by an attempt at emphatic clarity) or a wordy substitution (the latter driven by euphemistic intent, pedagogic intent, or sometimes loquaciousness alone). 

  • Necessary use of a phrase to circumvent either a vocabulary fault (of speaker or listener) or a lexical gap, either monolingually or in translation. 

  • An instance of such usage; a roundabout expression, whether an inadvisable one or a necessary one. 

euphemism

noun
  • The use of a word or phrase to replace another with one that is considered less offensive, blunt or vulgar than the word or phrase which it replaces. 

  • A word or phrase that is used to replace another in this way. 

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