n.
Function: adverb
Date: before 12th century
1 : in a firm or fixed manner <stuck fast >
2 : in a sound manner : DEEPLY < fast asleep>
3 a : in a rapid manner : QUICKLY b : in quick succession
4 : in a reckless or dissipated manner
5 : ahead of a correct time or schedule
6 archaic : CLOSE , NEAR