verb

• (intransitive) To collapse heavily or helplessly.
  "Exhausted, he slumped down onto the sofa."
• (intransitive) To decline or fall off in activity or performance.
  "Real estate prices slumped during the recession."
• (intransitive) To slouch or droop.
• (transitive) To lump; to throw together messily.
  "These different groups[…]are exclusively slumped together under that sense."

noun

• A heavy or helpless collapse; a slouching or drooping posture; a period of poor activity or performance, especially an extended period.
  "TOM. We haven't had sex with each other in five months. MICHAEL. We're in a slump, I know that.""
• (geology) A form of mass wasting in which a coherent mass of loosely consolidated materials or a rock layer moves a short distance down a slope.
• (geology, loosely) A crater or depression (an area where the ground slumps) which forms as a result of such wasting. (A large crater is colloquially called a megaslump.)
  "The biggest slump in the world - a mega-slump - is in the Russian taiga. Known as the Batagaika crater, it is a kilometre-long gash in the ground, about 70 metres deep, and growing[…]"
• (UK, dialect) A boggy place.
  "The road was all slumps of holes."