The Collaborative International Dictionary of English v.0.48:

Swelt \Swelt\, obs.
   imp. of Swell.
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The Collaborative International Dictionary of English v.0.48:

Swelt \Swelt\, v. i. [OE. swelten to die, to swoon or faint, AS.
   sweltan to die; akin to OD. swelten to hunger, to fail, OS.
   sweltan to die, Icel. svelta to die, to hunger, Sw.
   sv[aum]lta to hunger, Dan. sulte, Goth. sviltan to die. Cf.
   Swelter, Sweltry.]
   1. To die; to perish. [Obs.]
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   2. To faint; to swoon. [Obs.] --Chaucer.
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            Night she swelt for passing joy.      --Spenser.
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The Collaborative International Dictionary of English v.0.48:

Swelt \Swelt\, v. t.
   To overpower, as with heat; to cause to faint; to swelter.
   [Obs. or Prov. Eng.] --Bp. Hall.
   [1913 Webster]