Definition of "setback"

setback

/ˈsɛtbæk/

noun
plural setbacks
1. An obstacle, delay, disadvantage, blow (an adverse event which retards or prevents progress towards a desired outcome)
  Quotations
  The Constitutional Court has ruled today, November 17th, that Section 1448 of the Thai Civil and Commercial, stating that “a marriage can take place only between a man and a woman”, is constitutional under the Thai constitutional law. This decision could be a major setback for many Thai LGBTQ activist groups’ continued journey of what they call basic human rights to legally allow same-sex marriages in Thailand.
  2021 November 17, Nop Meechukhun, “Thailand’s Constitutional Court rules Section 1448 of heterosexual marriages lawful, LGBTQ rights groups ‘disappointed’”, in The Pattaya News‎, Bangkok: The Pattaya News Company Limited, retrieved 2021-11-17
2. (US) The required distance between a structure and a road.
3. (architecture) A step-like recession in a wall.
4. An offset to the temperature setting of a thermostat to cover a period when more or less heating is required than usual.
  Quotations
  Fuel savings from thermostat setbacks have long been accepted as fact, but little documentation existed to support it.
  1980, Popular Science, volume 217, number 4
5. (possibly archaic) A backset; a countercurrent; an eddy.
6. (archaic) A backset; a check; a repulse; a relapse.