How many letters does the top answer for “move unsteadily, with a rocking motion” have?

The most common answer is seesaw (6 letters).

Crossword clue: move unsteadily, with a rocking motion

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

seesaw 6 letters wn-def

a plaything consisting of a board balanced on a fulcrum; the board is ridden up and down by children at either end

teeter 6 letters wn-def

move unsteadily, with a rocking motion