The term 'fast asleep' is a phrase used to describe someone who is sleeping deeply and soundly. The crossword solutions for this term are OUT (3 letters), UNDER (5 letters), OUTLIKEALIGHT (13 letters), DEADTOTHEWORLD (14 letters), and INTHELANDOFNOD (14 letters). These solutions allude to the idea of being in a deep sleep, with phrases such as 'OUT like a light, ' 'dead to the world, ' and 'in the land of nod' suggesting a state of unconsciousness.