The Collaborative International Dictionary of English v.0.48:

Flannel \Flan"nel\ (fl[a^]n"n[e^]l), n. [F. flanelle, cf. OF.
   flaine a pillowcase, a mattress (?); fr. W. gwlanen flannel,
   fr. gwlan wool; prob. akin to E. wool. Cf. Wool.]
   1. A soft, nappy, woolen cloth, of loose texture. --Shak.
      [1913 Webster]

   2. a cotton fabric with a thick nap on one side, resembling
      flannel[1]; it is used, e. g. for underwear or sheets;
      also called flanellette.
      [PJC]

   3. pl. garments made of flannel, especially underwear.
      [PJC]

   4. a washcloth. [Brit.]
      [PJC]

   5. humbug; nonsensical or evasive talk. [Brit. informal]
      [PJC]

   6. insincere flattery or praise. [Brit. informal]
      [PJC]

   Adam's flannel. (Bot.) See under Adam.

   Canton flannel, Cotton flannel. See Cotton flannel,
      under Cotton.
      [1913 Webster] flannelbush

WordNet (r) 3.0 (2006):

flannel
    n 1: a soft light woolen fabric; used for clothing
    2: bath linen consisting of a piece of cloth used to wash the
       face and body [syn: washcloth, washrag, flannel, face
       cloth]
    3: (usually in the plural) trousers made of flannel or gabardine
       or tweed or white cloth [syn: flannel, gabardine,
       tweed, white]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "flannel":
   ballocks, blarney, bull, bullshit, bushwa, cock, crap, eyewash,
   flatter, flattery, hedge, hogwash, humbug, mislead, nonsense,
   prevarication, rubbish, shit, soft soap, soft-soap, sweet talk,
   sweet-talk, waffle, weasel words