puerile vs sibilant

puerile

adj

  • Childish; trifling; silly. 

  • Characteristic of, or pertaining to, a boy or boys; compare puellile. 

sibilant

adj

  • Characterized by a hissing or hushing sound such as the s or sh in sack or shack. 

noun

  • A consonant having a hissing or hushing sound such as the s or sh in sack or shack. 

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