Noun back down has 1 sense
  1. withdrawal, backdown, climb-down - a retraction of a previously held position
    --1 is a kind of retraction, abjuration, recantation
    Derived form: verb back down1
,Verb back down has 2 senses
  1. back up, back off, back down - move backwards from a certain position; "The bully had to back down"
    --1 is one way to withdraw, retreat, pull away, draw back, recede, pull back, retire, move back
    Derived form: noun backdown1
    Sample sentences:
    Something ----s
    Somebody ----s
  2. chicken out, back off, pull out, back down, bow out - remove oneself from an obligation; "He bowed out when he heard how much work was involved"
    --2 is one way to retire, withdraw
    Sample sentences:
    Somebody ----s
    Somebody ----s PP