Noun

• S: (n) waver (someone who communicates by waving)
• S: (n) hesitation, waver, falter, faltering (the act of pausing uncertainly) "there was a hesitation in his speech"
• S: (n) waver, flutter, flicker (the act of moving back and forth)

Verb

• S: (v) hesitate, waver, waffle (pause or hold back in uncertainty or unwillingness) "Authorities hesitate to quote exact figures"
• S: (v) falter, waver (be unsure or weak) "Their enthusiasm is faltering"
• S: (v) falter, waver (move hesitatingly, as if about to give way)
• S: (v) fluctuate, vacillate, waver (move or sway in a rising and falling or wavelike pattern) "the line on the monitor vacillated"
• S: (v) flicker, waver, flitter, flutter, quiver (move back and forth very rapidly) "the candle flickered"
• S: (v) waver, weave (sway from side to side)
• S: (v) quaver, waver (give off unsteady sounds, alternating in amplitude or frequency)