now vs valid

now

adj
  • Present; current. 

  • Fashionable; popular; up to date; current. 

conj
  • Since, because, in light of the fact; often with that. 

adv
  • Used to indicate a context of urgency. 

  • Sometimes; occasionally. 

  • Used to address a switching side, or sharp change in attitude from before. (In this usage, now is usually emphasized). 

  • At the present time. 

  • Used to introduce a point, a qualification of what has previously been said, a remonstration or a rebuke. 

  • At the time reached within a narration. 

  • Differently from the immediate past; differently from a more remote past or a possible future; differently from all other times. 

noun
  • The state of not paying attention to the future or the past. 

  • The present time. 

  • A particular instant in time, as perceived at that instant. 

intj
  • Indicates a signal to begin. 

valid

adj
  • Related to the current topic, or presented within context, relevant. 

  • Well grounded or justifiable, pertinent. 

  • Of an argument: whose conclusion is always true whenever its premises are true. 

  • Genuine - as distinguished from efficient or regular - sacrament. 

  • Of a formula or system: such that it evaluates to true regardless of the input values. 

  • Acceptable, proper or correct; in accordance with the rules. 

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