An unsteady motion.

A tremulous sound.

(music) A low-frequency oscillation sometimes used in dubstep.

(genetics) A variation in the third nucleotide of a codon that codes for a specific aminoacid.

(intransitive) To move with an uneven or rocking motion, or unsteadily to and fro.

(intransitive) To tremble or quaver.

(intransitive) To vacillate in one's opinions.

(transitive) To cause to wobble.