Dormido vs. adormecido
The Spanish words dormido and adormecido both relate to sleep, but they describe different states of rest. While dormido means that someone or something is completely asleep, adormecido describes a transitional state of being half-asleep, drowsy, or even physically numb.
Dormido
The word dormido describes the state of being fully and completely asleep.
El bebé está dormido en su cuna.
(The baby is asleep in his crib.)
Se quedó dormido durante la película.
(He fell asleep during the movie.)
No hagas ruido porque el perro está dormido.
(Do not make noise because the dog is asleep.)
Traté de llamarla pero ella ya estaba dormida.
(I tried to call her but she was already asleep.)
El guardia de seguridad fue encontrado dormido en el trabajo.
(The security guard was found asleep at work.)
Estaba tan cansado que cayó dormido al instante.
(He was so tired that he fell asleep instantly.)
Adormecido
The word adormecido describes a state of being half-asleep, drowsy, lethargic, or having a body part that is physically numb.
Me siento adormecido por la medicina para la alergia.
(I feel drowsy from the allergy medicine.)
El paciente todavía está adormecido después de la cirugía.
(The patient is still half-asleep after the surgery.)
Tengo el brazo adormecido por dormir sobre él toda la noche.
(My arm is numb from sleeping on it all night.)
Se despertó adormecido y muy confundido por la mañana.
(He woke up groggy and very confused in the morning.)
El intenso calor de la tarde me dejó completamente adormecido.
(The intense afternoon heat left me completely sleepy.)
Sentía los pies adormecidos por caminar en la nieve.
(She felt her feet numb from walking in the snow.)
Summary
To choose the correct word, use dormido when someone is fully in a deep state of sleep. On the other hand, use adormecido to describe someone who is drowsy, groggy, heavily medicated, or to describe a specific body part that has gone numb.