ガクガク

adverb, adverb taking the 'to' particle, na-adjective, noun or participle which takes 'suru'

trembling; shaking; chattering (of teeth)

Describes involuntary shaking from fear, cold, or nervousness. Often used with 震える or する.

• 寒さむくて歯はがガクガクした。

  My teeth were chattering from the cold.

• 彼かれは恐きょう怖ふでガクガク震ふるえていた。

  He was trembling with fear.

adverb, adverb taking the 'to' particle, na-adjective, noun or participle which takes 'suru'

wobbly; loose; shaky

Describes something physically unstable, such as a loose joint or an unsteady object. Often used with する or なる.

• この机つくえの脚あしがガクガクする。

  The legs of this desk are wobbly.

• ネジが緩ゆるんでガクガクになった。

  The screw came loose and it became wobbly.