waver russian

• дро́гнуть

  shiver flinch or waver

• колеба́ться

  to hesitate/to range/fluctuate, vacillate, waver

• заколеба́ться

  begin to hesitate, become unsteady, begin to waver

• ша́ткий

  unsteady, shaky, rickety, precarious, wavering, weak