According to the Merriam-Webster dictionary,

HIBERNATION:

1 : to pass the winter in a torpid or resting state

2 : to be or become inactive or dormant

According to Rohene,

HIBERNATION:

Time when animals go dormant ‘cos of extreme cold and hot.

According to me,

HIBERNATION:

Time when Angel goes into deep sleep after extreme exhaustion or tortures such as two grueling exams in a day!