let down vs strut

let down

verb
  • To allow to descend. 

  • To disappoint; to betray or fail somebody 

  • To reduce one's level of effort. 

  • To soften in tempering. 

  • Used other than figuratively or idiomatically: see let, down. 

  • To lengthen by undoing and resewing a hem. 

strut

verb
  • To be attached diagonally or at a slant; also, to be bent at a sharp angle. 

  • Of a peacock or other fowl: to stand or walk stiffly, with the tail erect and spread out. 

  • To walk across or on (a stage or other place) haughtily or proudly. 

  • To walk haughtily or proudly with one's head held high. 

  • To brace or support (something) by a strut or struts; to hold (something) in place or strengthen by a diagonal, transverse, or upright support. 

noun
  • A beam or rod providing support. 

  • An act of strutting (“bracing or supporting (something) by a strut or struts (sense 1); attaching diagonally; bending at a sharp angle”); specifically, deviation (of the spoke of a wheel) from the normal position. 

  • An instrument for adjusting the pleats of a ruff. 

  • A step or walk done stiffly and with the head held high, often due to haughtiness or pride; affected dignity in walking. 

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