This is the 1512th most frequent Portuguese word.
energético
Stimulating, invigorating, or related to energy.
In this sentence, 'energético' is an adjective describing the juice as something that provides energy or revitalization.
Este suco é muito energético.
This juice is very energizing.
Here, 'energético' is used as a noun referring to an energy drink, which is a type of beverage intended to boost energy levels.
Preciso de um energético antes de ir para a academia.
I need an energy drink before going to the gym.
In this case, 'energético' serves as an adjective modifying 'desempenho', indicating its relation to energy or power output.