Webster’s Revised Unabridged Dictionary · 1913
Slump
Slump (slŭmp), n. [Cf. D. slomp a mass, heap, Dan. slump a quantity, and E. slump, v.t.] The gross amount; the mass; the lump. [Scot.]
Slump, v. t. [Cf. Lump; also Sw. slumpa to bargain for the lump.] To lump; to throw into a mess.
These different groups . . . are exclusively slumped together under that sense. Sir W. Hamilton.
Slump, v. i. [imp. & p. p. Slumped; p. pr. & vb. n. Slumping.] [Scot. slump a dull noise produced by something falling into a hole, a marsh, a swamp.] To fall or sink suddenly through or in, when walking on a surface, as on thawing snow or ice, partly frozen ground, a bog, etc., not strong enough to bear the person.
The latter walk on a bottomless quag, into which unawares they may slump. Barrow.
Slump, n. 1. A boggy place. [Prov. Eng. & Scot.]
2. The noise made by anything falling into a hole, or into a soft, miry place. [Scot.]