foe
Faked or fraud.
Fumes are a synonym for gas.
Finish is another word for completion starting with the letter F.
lens opening; lens diaphragm some might suggest F-Stop
Friggot
Forerunner is a synonym for leader. It begins with the letter F.
the synonym of ride can be to drive or to f***.
Fossil is a synonym of old and antique and begins with an F.
Check an online thesaurus (like thesaurus.com) using Control-F (Find) key (spacebar-k).
Faked or fraud.
A synonym for "good" that starts with an "F" is "favorable." This word conveys a positive or advantageous quality, often used to describe conditions or outcomes that are beneficial.
enemy
Friend
footstep is a synonym for pace
frugal
faint?foggy?
Fumes are a synonym for gas.