purring

from The Collaborative International Dictionary of English v.0.48

Pur \Pur\, v. i. [imp. & p. p. {Purred}; p. pr. & vb. n.
   {Purring}.] [Of imitative origin; cf. Prov. G. purren.]
   To utter a low, murmuring, continued sound, as a cat does
   when pleased. [Written also {purr}.]
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

39 Moby Thesaurus words for "purring":
      beaming, beatific, beatified, birring, blessed, blissful,
      bombilation, bombinating, bombination, booming, burring, buzzing,
      capering, cheerful, chirping, dancing, droning, flushed with joy,
      gay, glad, glowing, happy, hum, humming, joyful, joyous, laughing,
      leaping, low rumbling, radiant, singing, smiling, smirking,
      sparkling, starry-eyed, thrice happy, thrumming, whirring,
      whizzing

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