teetering (?.)

• Lissajous figure
• alternation
• back-and-forth
• coming and going
• dilapidated
• doddering
• ebb and flow
• fluctuation
• flux and reflux
• groggy
• oscillation
• pendulation
• ramshackle
• reciprocation
• rhythmic play
• ricketish
• rickety
• rocky
• seesaw
• seesawing
• shaky
• shifting
• shuffling
• sine wave
• spidery
• spindly
• teeter
• teeter-totter
• teeter-tottering
• teetery
• to-and-fro
• tottering
• tottery
• tumbledown
• unsteady
• ups and downs
• vacillation
• variation
• vicissitude
• wavering
• wigwag
• wobbly