if only vs inasmuch as

if only

conj
  • Even if for no other reason than; only just. 

  • Used other than figuratively or idiomatically: see if, only. 

  • I wish that; signifies a wish or desire for the present or the future. 

  • I wish that; signifies a regret about an action in the past. 

inasmuch as

conj
  • Because of the fact that; since. 

  • To the extent that; insofar as. 

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