The phrase "the arms of Morpheus" refers to a deep and restful sleep, named after the Greek god of dreams. There are many synonyms that can be used to describe this type of slumber, including "a sound slumber," "a blissful sleep," "a peaceful rest," "a tranquil doze," "a serene nap," "a deep drowse," and "a refreshing snooze." Each of these phrases implies a state of peaceful relaxation and the absence of stress or worry. They all evoke a sense of comfort and contentment, coupled with the feeling of being completely at ease. Whether you use "the arms of Morpheus" or one of these other phrases, the effect is always one of deep and restful sleep.