Here is our list of American idioms that start with "G":

Gaydar (n.): The ability to tell whether or not someone is gay. Example: "My gaydar was a little off. I was sure he was straight."

Gawk (v.): To stare (stupidly). Example: "Those men were gawking at us."

Geek (n.): A (slightly) strange person who is obsessed with things such as music, electronics, video games, etc.

Get (v.): To understand. Examples: "I don't get it.", "I don't get him."

(To) get a move on:
To go or do something quickly, to get going, etc. Example: "Hey if we want to make the 8:00 PM show we should get a move on."

(To) get carried away:
To exaggerate/ go too far/ to become emotional. Example: "I got carried away. I bought 10 shirts!"; "She got carried away when she started talking about the war."

(To) get caught up:
To become involved, especially emotionally. Example: "I just got caught up in his plan and couldn't think straight."

(To) get cold feet:
To become timid or frightened. Example: "I usually get cold feet when I have to speak in public."

(To) get down to business:
To start working seriously. Example: "Enough playing around. Let's get down to business."

Get a kick out of (something): To enjoy (something) Example: "Why does he get such a kick out of watching her suffer?"

(To) get one's fill (or fix) of something:
To have enough of something. To have a lot of something. Example: "She's had her fill of his lying ways."

(To) get one's foot in the door:
To get started in a process; to attain a favorable position which will help one work toward a goal. Example: "I'm trying to find a better job, but I can't get my foot in the door."

To get one's mind off (something): To stop thinking about (something). Example: "The night out really helped me get my mind off my problems for a while."

(To) get on someone's nerves:
To annoy someone; to bother or irritate someone. Example: "I know that he's harmless, but he still gets on my nerves for some reason."

(To) get rid of (something/someone):
To eliminate. To throw away. To hide. Examples: "This detergent gets rid of dirt better than any other one that I've used."; "Get rid of the cigarette! Your mother's coming!"

(To) get something off one's chest:
To say something that has been on your mind; to say something that has been bothering you. Example: "Did you tell her about Hawaii? Yes, and I felt much better once I got that off my chest."

(To) get something straight:
To clarify something. To understand something clearly. Example: "Let me get this straight. Your mother's cousin stole money from your father's cousin's daughter?"

(To) get that all the time:
To hear something constantly. Example: "P1: Hey, you really look like Brad Pitt! P2: Yeah, I get that all the time."

(To) get the blues:
To become sad or depressed.

Get to the point: To be direct. Example: "Stop beating around the bush and get to the point!"

Gig: Concert (when talking about musicians/bands); An acting engagement (when talking about actors).

Give me a break: This phrase can be used to 1) express disbelief at something you think is untrue ("You went out with Miss America? Give me a break!"), or 2) to express disbelief that something is ridiculous (but true), expensive, etc. ("$2000 per month for this apartment?? Give me a break!")

(To) give someone a call:
To call someone (on the telephone). Example: "I'll give you call tomorrow morning."

(To) give someone the benefit of the doubt:
To believe in someone despite information that makes them seem guilty of something. Example: "Hey, don't believe the rumors. Give him the benefit of the doubt."

(To) give someone a piece of one's mind:
To bawl someone out. To let someone know how one really feels. Example: "After that driver took my parking spot, I really gave him a piece of my mind."

Glitzy (adj.): Fancy, expensive. Example: "A glitzy hotel"

Glued to one's seat: To be "glued to one's seat" means to be so interested in something that one is unwilling/unable to move from where one is sitting.

(To be) a go: To happen. Most often heard in expressions such as "It's a go." (It's going to happen), "I thought it was a go" (I thought it was going to happen), etc.

(A) go-getter:
*somewhat outdated* An aggressive employee; a hard worker. Example: "Jim is a real go-getter."

(To) go Dutch:
To pay for oneself when going out in a group.

(To) go overboard:
To do too much; to exaggerate. Example: "They really went overboard with the party preparations."

(To) go up in flames:
To burn; to be consumed in flames. Example: "The house went up in flames and the firefighters had a hard time putting out the fire."

(To) go over something with a fine toothed comb:
To go over something very carefully, especially checking for errors. Example: "Here's the report. Make sure to go over it with a fine toothed comb."

(To) go to someone's head:
To make someone overly conceited or proud. Example: "That award that he won really went to his head."

Go with (v.): To choose. To decide on. Example: "I'm gonna go with the blue shirt." (I've decided on the blue shirt.)

Go with the flow (v.): To accept things (the way they are). Example: "I'm just gonna go with flow and see what happens."

(A) golden opportunity:
A good chance to succeed, a good investment. Example: "I didn't have enough money to buy that restaurant. I missed a golden opportunity."

Gonna: Short for "going to". Example: "I'm gonna call you tomorrow."

Gotta: Short for "have got to" or "have to". Example: "I gotta go."

Grass (n.): Marijuana; Pot.

Gross (adj.): Disgusting. Example: "That's gross!"

Grub (n.): Slightly rude term for "food".

Gut: Belly. Example: "I lost my gut when I stopped drinking beer."

Guts: Courage. Example: "You don't have the guts to do that."