Definition of "mouthing"

mouthing

verb
1. present participle and gerund of mouth
noun
plural mouthings
1. The act of forming a shape with the mouth, especially as part of sign language.
  Quotations
  Mouthings tend to occur most often when signers are manually articulating nouns, open-class items, and morphologically simpler signs (see Crasborn et al. 2008).
  2013, Robert Bayley, Richard Cameron, Ceil Lucas, The Oxford Handbook of Sociolinguistics, page 382
2. Ranting; passionate speech devoid of meaning.
  Quotations
  Kearn did not rant, he did not deafen you with heroics and empty mouthings.
  1941, Players Magazine