stealth vs undercover

stealth

adj
  • Surreptitious; secret; not openly acknowledged. 

  • Having properties that diminish radar signatures. 

  • Hiding one's transgender status (in general or in specific areas of one's life, e.g. at work) after transition. 

verb
  • To conceal or infiltrate through the use of stealth. 

  • To have sexual intercourse without a condom through deception (for example, removing the condom mid-act). 

noun
  • The attribute or characteristic of acting in secrecy, or in such a way that the actions are unnoticed or difficult to detect by others. 

adv
  • While hiding one's transgender status from society after transition. 

undercover

adj
  • Performed or happening in secret. 

  • Employed or engaged in spying or secret investigation. 

verb
  • To provide too little coverage. 

noun
  • A person who works undercover. 

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