waver
noun
someone who communicates by waving
the act of pausing uncertainly
“there was a hesitation in his speech”
the act of moving back and forth
verb
pause or hold back in uncertainty or unwillingness
“Authorities hesitate to quote exact figures”
be unsure or weak
“Their enthusiasm is faltering”
Synonymsfaltermove hesitatingly, as if about to give way
Synonymsfaltermove or sway in a rising and falling or wavelike pattern
“the line on the monitor vacillated”
move back and forth very rapidly
“the candle flickered”
sway from side to side
Synonymsweavegive off unsteady sounds, alternating in amplitude or frequency
Synonymsquaver
Source: WordNet 3.1, Princeton University