This is the 5028th most frequent Spanish word.
escondido
Hidden.
In this sentence, 'escondido' is used as a past participle indicating the state of being hidden.
El libro está escondido debajo de la cama.
The book is hidden under the bed.
Here, 'escondido' functions as part of a reflexive verb 'se ha escondido,' describing the action of hiding oneself.
Se ha escondido porque no quiere que lo encuentren.
He has hidden himself because he doesn't want to be found.
'Escondido' in this case is an adjective describing the noun 'secreto,' indicating the secret's characteristic of being hidden.