alert vs listening

alert

adj
  • Attentive; awake; on guard. 

verb
  • To give warning to. 

noun
  • An alarm. 

  • A state of readiness for potential combat. 

  • A notification of higher importance than an advisory. 

listening

adj
  • Of an action that is performed with caution and attention to sounds. 

  • Of something that is used in order to hear or to improve the ability to hear. 

  • Of something or someone that listens. 

noun
  • Skill or ability of perceiving spoken language. 

  • Action of the verb listening 

  • An educational exercise involving listening 

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