Definition of "ratchet"

ratchet¹

/ˈɹæt͡ʃɪt/

noun
plural ratchets
1. A pawl, click, or detent for holding or propelling a ratchet wheel, or ratch, etc.
2. A mechanism composed of a ratchet wheel, or ratch and pawl.
3. A ratchet wrench.
4. (by extension) A procedure or regulation that goes in one direction, usually up.
  Quotations
  The threat of terrorism to the British lies in the overreaction to it of British governments. Each one in turn clicks up the ratchet of surveillance, intrusion and security. Each one diminishes liberty.
  2012 December 14, Simon Jenkins, “We mustn't overreact to North Korea boys' toys”, in The Guardian Weekly‎, volume 188, number 2, page 23
5. A noisemaker or musical instrument where sound is generated by a board striking against a rotating gear. See gragger, raganella.
verb
third-person singular simple present ratchets, present participle ratcheting, simple past and past participle ratcheted
1. (transitive) To cause to become incremented or decremented.
2. (intransitive) To increment or decrement.

ratchet²

/ˈɹæt͡ʃɪt/

adjective
comparative more ratchet, superlative most ratchet
1. (US, slang) Ghetto; unseemly, indecorous.
  Quotations
  The one thing that always accompanies Miley's ratchet look (along with the gang signs) is the tongue, which is sort of like saying this persona that she has adopted is some sort of gonzo idiot who can't keep its tongue in her head.
  2013 September 24, Elspeth Reeve, Brian Moylan, “Miley Cyrus's Tongue: A Debate”, in The Atlantic
  The feminine-meets-fiesty creations are right on par with all the reasons we love the rightgeously[sic] ratchet “Work” singer — and she knows it.
  2016 April 19, Julee Wilson, “Rihanna's Latest Sock Collection is Exactly What You'd Expect...and More”, in Essence
  Classy in the streets but we ratchet
  2018 March 28, Todrick Hall (lyrics and music), “T.H.U.G. (Trade)”, in Forbidden‎, track 14