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

The Collaborative International Dictionary of English v.0.48:

Smoulder \Smoul"der\, v. i.
   See Smolder.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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