The Collaborative International Dictionary of English v.0.48:

Smolder \Smol"der\, Smoulder \Smoul"der\, v. i. [imp. & p. p.
   Smolderedor Smouldered; p. pr. & vb. n. Smoldering or
   Smouldering.] [OE. smolderen; cf. Prov. G. sm["o]len,
   smelen, D. smeulen. Cf. Smell.]
   1. To burn and smoke without flame; to waste away by a slow
      and supressed combustion.
      [1913 Webster]

            The smoldering dust did round about him smoke.
                                                  --Spenser.
      [1913 Webster]

   2. To exist in a state of suppressed or smothered activity;
      to burn inwardly; as, a smoldering feud.
      [1913 Webster] Smolder

The Collaborative International Dictionary of English v.0.48:

Smolder \Smol"der\, Smoulder \Smoul"der\, v. t.
   To smother; to suffocate; to choke. [Obs.] --Holinshed.
   Palsgrave.
   [1913 Webster] Smolder

The Collaborative International Dictionary of English v.0.48:

Smolder \Smol"der\, Smoulder \Smoul"der\, n.
   Smoke; smother. [Obs.]
   [1913 Webster]

         The smolder stops our nose with stench.  --Gascoigne.
   [1913 Webster] Smoldering

WordNet (r) 3.0 (2006):

smolder
    n 1: a fire that burns with thick smoke but no flame; "the
         smoulder suddenly became a blaze" [syn: smoulder,
         smolder]
    v 1: burn slowly and without a flame; "a smoldering fire" [syn:
         smolder, smoulder]
    2: have strong suppressed feelings [syn: smolder, smoulder]

Moby Thesaurus II by Grady Ward, 1.0:

108 Moby Thesaurus words for "smolder":
   bake, be angry, be excitable, be in heat, be latent, be livid,
   be pissed, bellow, blaze, bloom, blow a gasket, blow up, bluster,
   boil, broil, browned off, bubble, burn, burst, carry on,
   catch fire, catch the infection, chafe, choke, churn, combust,
   come apart, cook, erupt, escape notice, excite easily, explode,
   ferment, fire up, flame, flame up, flare, flare up, flash up,
   flicker, flip, flush, fret, fry, fulminate, fume, fust, gasp,
   get excited, glow, go into hysterics, go on, hang fire,
   have a conniption, have a tantrum, hibernate, hit the ceiling,
   idle, incandesce, lie beneath, lie dormant, lie hid, lie low, lurk,
   make no sign, moil, pant, parch, pissed off, radiate heat, rage,
   raise Cain, raise hell, raise the devil, raise the roof, ramp,
   rant, rant and rave, rave, roast, run a temperature, scald, scorch,
   seethe, shimmer with heat, simmer, sizzle, sleep, slumber, smoke,
   smother, spark, stagnate, steam, stew, stifle, stir, storm,
   suffocate, sweat, swelter, take fire, take on, throw a fit, toast,
   turn a hair, underlie, vegetate