clean as a whistle vs simple

clean as a whistle

adj
  • Completely innocent; beyond moral reproach. 

  • Very clean 

simple

adj
  • Free from duplicity; guileless, innocent, straightforward. 

  • Consisting of a single individual or zooid; not compound. 

  • Consisting of one single substance; uncompounded. 

  • Undistinguished in social condition; of no special rank. 

  • Without ornamentation; plain. 

  • Of a group: having no normal subgroup. 

  • Homogenous. 

  • Feeble-minded; foolish. 

  • Using steam only once in its cylinders, in contrast to a compound engine, where steam is used more than once in high-pressure and low-pressure cylinders. 

  • Not compound, but possibly lobed. 

  • Uncomplicated; taken by itself, with nothing added. 

noun
  • Part of the apparatus for raising the heddles of a drawloom. 

  • A herbal preparation made from one plant, as opposed to something made from more than one plant. 

  • A feast which is not a double or a semidouble. 

  • A drawloom. 

  • A simple or atomic proposition. 

How often have the words clean as a whistle and simple occurred in a corpus of books? (source: Google Ngram Viewer )