any vs whatever

any

det
  • No matter what kind. 

  • One at all; at least one; at least one kind of; some; a positive quantity of. 

adv
  • To even the slightest extent, at all. 

pron
  • Any thing(s) or person(s). 

whatever

det
  • Any; of no matter what type or kind. 

  • What ever; emphatic form of 'what'. 

  • Regardless of the ... that; for any ... that. 

  • Any ... that; of no matter what type or kind that. 

noun
  • Something whose exact kind or nature is unimportant; a thingy. 

adj
  • Unexceptional or unimportant; blah. 

adv
  • In what way; to what extent. 

  • At all; in any way; whatsoever. 

pron
  • Anything; thing(s) of unspecified kind, or no matter what kind; sometimes used to indicate that the speaker does not care about options. 

  • Anything that; all that. 

  • Regardless of anything that. 

  • What ever; emphasised form of 'what', used to ask which thing, event, circumstance, etc. 

intj
  • A holophrastic expression used to dismiss something that the speaker doesn't care about, doesn't think important, or doesn't want to consider or discuss any further. 

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