if vs though

if

conj
  • Even if; even in the circumstances that. 

  • Although; used to introduce a concession. 

  • Supposing that; given that; supposing it is the case that. 

  • Supposing that; used with past or past perfect subjunctive indicating that the condition is closed. 

  • Supposing that, assuming that, in the circumstances that; used to introduce a condition or choice. 

  • Whether; used to introduce a noun clause, an indirect question, that functions as the direct object of certain verbs. 

  • In the event that a statement is true (a programming statement that acts in a similar manner). 

  • Introducing a relevance conditional. 

noun
  • An uncertainty, possibility, condition, doubt etc. 

though

conj
  • Despite the fact that; although. 

adv
  • Used to intensify statements or questions; indeed. 

  • Despite that; however. 

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