Crank up is a verb phrase that means to increase, intensify, or start something. Synonyms for this phrase include escalate, raise, boost, augment, enhance, amplify, heighten, intensify, and ratchet up. These words add greater emphasis and energy to the action being described. For instance, one can "crank up" the volume on a device, but using "intensify" adds a more dynamic and urgent tone. Similarly, one can "crank up" a car engine, but "amp up" or "escalate" adds a more intense and powerful connotation. Synonyms for "crank up" can be used to vary word choice and add more diverse language to writing and speech.