rickety, shaky, wobbly, wonky -- (inclined to shake as from weakness or defect; "a rickety table"; "a wobbly chair with shaky legs"; "the ladder felt a little wobbly"; "the bridge still stands though one of the arches is wonky")
shaky, shivering, trembling -- (vibrating slightly and irregularly; as e.g. with fear or cold or like the leaves of an aspen in a breeze; "a quaking bog"; "the quaking child asked for more"; "quivering leaves of a poplar tree"; "with shaking knees"; "seemed shaky on her feet"; "sparkling light from the shivering crystals of the chandelier"; "trembling hands")
precarious, shaky -- (not secure; beset with difficulties; "a shaky marriage")