Oscillate (verb)

1. To swing or move back and forth regularly and repeatedly, often with a slight irregularity.
2. To fluctuate between two or more states, opinions, or conditions.

Origin:

From latin oscillatus, past participle of oscillare ("to swing, waver"), from oscillum ("a small swing"), from os ("mouth") + -cillum (diminutive suffix).

Examples:

1. The pendulum oscillates back and forth with a steady rhythm.
2. The bridge oscillated in the wind, making it difficult to cross.
3. The stock market oscillates, with prices rising and falling regularly.
4. He oscillated between different options before making a decision.
5. The politician's opinions oscillated depending on the audience he was addressing.