Source : Webster's Revised Unabridged Dictionary (1913)

Querulous \Quer"u*lous\, a. [L. querulus and querulosus, fr.
   queri to complain. Cf. {Cry}, v., {Quarrel} a brawl,
   {Quarrelous}.]
   1. Given to quarreling; quarrelsome. [Obs.] --land.

   2. Apt to find fault; habitually complaining; disposed to
      murmur; as, a querulous man or people.

            Enmity can hardly be more annoying that querulous,
            jealous, exacting fondness.           --Macaulay.

   3. Expressing complaint; fretful; whining; as, a querulous
      tone of voice.

   Syn: Complaining; bewailing; lamenting; whining; mourning;
        murmuring; discontented; dissatisfied. --
        {Quer"u*lous*ly}, adv. -- {Quer"u*lous*ness}, n.

Source : WordNet®

querulousness
     n : the quality of being given to complaining