1. Facetious: Intended to be humorous, but often silly or inappropriate. Playful and communicated in jest. That which is frivolous or wryly humorous is facetious; Slightly funny. Joking.

The teacher taught in a facetious manner.

2. Fastidious: Concerned over the perfection of even the smallest detail. Meticulous and exacting; compulsive in terms of cleanliness.

The students did not exhibit even the smallest aspects of a fastidious nature.

3. Flippant: Showing a lack of appropriate seriousness. Not that serious. A disrespectful disregard for decorum, often expressed by tactless chatter and jabber.

The student reacted in a flippant manner.

4. Fruition: The point at which something comes to maturity. Reaches a desired outcome. Finished, completed, matured. Literally and figuratively means “to fruit”.

The villain’s evil plans finally came to fruition.

5. Furtive: Surreptitious, sly, stealthy, meant to escape detection. Sneaky. A person with something to hide.

The student’s behavior depicted a furtive nature.

6. Guile: Cunning, deceitful, and treacherous quality or type of behavior. Skill and cleverness used to trick, deceive, or mislead people.

No matter how smart you think you are, you are no match for the guile of an experienced con artist trying to separate you from your money.

7. Gamut: The full range or extent. Entire series or sequence. All of it.

The athletic trainer really put us through the gamut of exercises today.

8. Garrulous: excessively talkative; using way too many words. Extremely verbose.

These kids are so garrulous today; they never shut up!

9. Gerrymander: to divide an electoral district so as to give a political advantage to a particular party. To divide a geographic area into voting districts so as to give advantage to one part in elections.

10. Gregarious: Very friendly, sociable, outgoing, or cordial; happy in the company of others.

His personality was gregarious - everywhere he went he was smiling and laughing.