The Collaborative International Dictionary of English v.0.48:

Smug \Smug\, a. [Of. Scand. or Low German origin; cf. LG. smuck,
   G. schmuck, Dan. smuk, OSw. smuck, sm["o]ck, and E. smock,
   smuggle; cf. G. schmuck ornament. See Smock.]
   Studiously neat or nice, especially in dress; spruce;
   affectedly precise; smooth and prim.
   [1913 Webster]

         They be so smug and smooth.              --Robynson
                                                  (More's
                                                  Utopia).
   [1913 Webster]

         The smug and scanty draperies of his style. --De
                                                  Quincey.
   [1913 Webster]

         A young, smug, handsome holiness has no fellow. --Beau.
                                                  & Fl.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Smug \Smug\, v. t. [imp. & p. p. Smugged; p. pr. & vb. n.
   Smugging.]
   To make smug, or spruce. [Obs.]
   [1913 Webster]

         Thus said, he smugged his beard, and stroked up fair.
                                                  --Dryton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

smug
    adj 1: marked by excessive complacency or self-satisfaction; "a
           smug glow of self-congratulation" [syn: smug, self-
           satisfied]

Moby Thesaurus II by Grady Ward, 1.0:

115 Moby Thesaurus words for "smug":
   Quakerish, Victorian, bland, bovine, braw, buttery, censorious,
   chic, classy, clothes-conscious, complacent, conceited,
   consequential, cosmopolitan, dapper, dashing, deck out, demure,
   disarming, doll up, dress up, dressed to advantage,
   dressed to kill, elegant, exquisite, fair-spoken, fine-spoken,
   fulsome, genteel, glib, gussy up, hidebound, holier-than-thou,
   honey-mouthed, honey-tongued, ingratiating, jaunty, mid-Victorian,
   narcissan, narcissine, narcissistic, narcistic, narrow, natty,
   neat, nifty, nobby, oily, oily-tongued, old-maidish, overconfident,
   overmodest, overproud, overweening, posh, priggish, prim, primp,
   prudish, puritanical, recherche, ritzy, sanctimonious,
   self-admiring, self-approving, self-assuming, self-complacent,
   self-congratulating, self-congratulatory, self-content,
   self-contented, self-delighting, self-endeared, self-esteeming,
   self-gratulating, self-gratulatory, self-important, self-loving,
   self-respecting, self-satisfied, self-sufficient, sharp, sleek,
   slick, smart, smarten up, smooth, smooth-spoken, smooth-tongued,
   snazzy, soapy, soft-spoken, soigne, soignee, sophisticated, spiffy,
   spruce, spruce up, stiff-necked, straitlaced, stuffy,
   style-conscious, suave, suave-spoken, swank, swanky, swell,
   tricksy, trig, trim, unctuous, vain, vainglorious, well-dressed,
   well-groomed



V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

SMUG
       Seldom Met Users Group [book] (HP, HP 3000)