This is the 11712th most frequent Portuguese word.
plenos
"Plenos" means "full" or "complete" in English.
The word 'plenos' here is used as an adjective to indicate that the preparations are complete, thorough, and fully ongoing.
Estamos em plenos preparativos para a festa.
We are in full preparations for the party.
'Plenos' is used to express the state of totality or completeness regarding the enjoyment experienced during the vacation.
Eles aproveitaram os dias de férias em plenos.
They enjoyed the vacation days in fullness.
Here, 'plenos' describes the intensity or completeness of the thoughts in his mind.