cos vs whenever

cos

conj

  • because 

noun

  • A variety of lettuce with long, crisp leaves. 

  • A cousin, cuz. 

whenever

conj

  • When. 

  • Every time that. 

  • At any time that. 

  • Regardless of the time that. 

  • At the (single) time that, no matter when. 

adv

  • When ever: emphatic form of when. 

  • At any time. 

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