fast

adjective

1
(of a photographic lens or emulsion) causing a shortening of exposure time
a fast lens
2
unwavering in devotion to friend or vow or cause
a firm ally
loyal supporters
3
acting or moving or capable of acting or moving quickly
fast film
on the fast track in school
4
at a rapid tempo
the band played a fast fox trot
5
(used of timepieces) indicating a time ahead of or later than the correct time
my watch is fast
6
securely fixed in place
the post was still firm after being hit by the car
7
hurried and brief
paid a flying visit
took a flying glance at the book
8
unrestrained by convention or morality
Congreve draws a debauched aristocratic society
deplorably dissipated and degraded
9
resistant to destruction or fading
fast colors

1
abstain from eating
Before the medical exam, you must fast
2
abstain from certain foods, as for religious or medical reasons
Catholics sometimes fast during Lent

Also useful for “fast”:Unscrambler— Turn loose letters into real words