Something that fluctuates varies or changes — it's the opposite of steady. Like the ups and downs of the stock market or the relationship status of a Hollywood starlet.

Fluctuate is a verb that describes movement, sometimes irregular, but often rising and falling in a wave-like pattern. The tides fluctuate according to the weather and season, for example. Your emotions fluctuate depending on what happens throughout the day, and so does your weight. In fact, you usually weigh less in the morning, before you've eaten. You're also taller, since your spine compresses as you walk around. So your height fluctuates, too.

Definitions of fluctuate

v move or sway in a rising and falling or wavelike pattern

vacillate, waver
Type of:
alternate dramatically between high and low values

v cause to fluctuate or move in a wavelike pattern

vacillate, waver
move or sway in a rising and falling or wavelike pattern
Type of:
displace, move
cause to move or shift into a new position or place, both in a concrete and in an abstract sense

v be unstable

“The stock market fluctuates
Type of:
change state, turn
undergo a transformation or a change of position or action

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