General opposites:
* Agitado: This means "agitated" or "excited" and is a general opposite of "tranquilo" in terms of calmness and composure.
* Inquieto: This means "restless" or "uneasy" and implies a lack of peacefulness.
* Nervioso: This means "nervous" and suggests anxiety or apprehension.
Specific opposites:
* Ajetreado: This means "busy" or "hectic" and contrasts with "tranquilo" in terms of pace and activity level.
* Preocupado: This means "worried" and implies a lack of peace of mind.
* Estresado: This means "stressed" and emphasizes the negative emotional state.
Informal opposites:
* Movido: This means "lively" or "animated" and suggests a lack of tranquility in a more positive way.
* Cansado: This means "tired" and can be used to contrast with "tranquilo" in terms of energy levels.
Ultimately, the best opposite of "tranquilo" will depend on the specific situation and the desired meaning.