poikilothermy

As a verb fluctuate

is to vary irregularly; to swing.

As a noun poikilothermy is

(biology) the quality of having a body temperature that varies or fluctuates, depending on the temperature of the environment; cold-bloodedness.

As nouns the difference between quality and poikilothermy

is that quality is (uncountable) level of excellence while poikilothermy is (biology) the quality of having a body temperature that varies or fluctuates, depending on the temperature of the environment; cold-bloodedness.

As an adjective quality

is being of good worth, well made, fit for purpose.

Poikilothermy is a related term of poikilothermic.

As a noun poikilothermy

is (biology) the quality of having a body temperature that varies or fluctuates, depending on the temperature of the environment; cold-bloodedness.

As an adjective poikilothermic is

(of an animal) having a body temperature that varies depending on the outside temperature.