falter in WordNet English dictionary

1. speak haltingly
   "The speaker faltered when he saw his opponent enter the room"
   bumble  stutter  stammer  falter 
   
2. walk unsteadily
   "The drunk man stumbled about"
   stumble  falter  bumble 
   
3. move hesitatingly, as if about to give way
   falter  waver 
   
4. be unsure or weak
   "Their enthusiasm is faltering"
   falter  waver 
   

1. the act of pausing uncertainly
   "there was a hesitation in his speech"
   hesitation  waver  falter  faltering