1. He is reft-handed.

2. He is right-handed.
3. He is ambidextrous.

4. He is a right-handed person.
5. He is a left-handed person.
6. He is an ambidextrous person.
7. He is an ambidexter.

(Are all the expressions f grammatical? Do you have some more common expressions?)

8. Look at the guy!

(In this sentence, does 'the guy' mean only a male? Or does 'the guy' can mean a female?)

9. You guys are wroking very hard in the workplace.
(Is this one correct? In this sentence 'You' and 'guys' are in apposition, right? Which preposition do I have to use 'in' or'at' before the workplace? are both propositions OK?)

1. left-handed

#s 1 - 6 are all correct and commonly used. But in 7, the word "ambidexter" is obsolete and no longer used.

8. The word "guy" here is male.

9. However, in this sentence, "guys" may refer to both males and females. I don't like to be referred to as one of the "guys," though.

Guys is used as an appositive modifying You. Either preposition is correct.

All of the expressions from 1 to 7 are grammatically correct. However, "ambidexter" is not a commonly used word.

In sentence 8, if you say "Look at the guy!" it generally implies that you are referring to a male. However, in some casual contexts, "guy" can sometimes be used as a gender-neutral term, similar to how "dude" is sometimes used.

Regarding sentence 9, "You guys are working very hard in the workplace" is correct. In this sentence, "you guys" is a colloquial way of addressing a group of people, and it is in apposition to "You." Both "in" and "at" can be used before "the workplace," but the choice depends on the specific context. If you want to highlight the physical location where the work is being done, you can use "at." If you want to emphasize the broader concept of the workplace, including the environment and dynamics, you can use "in."

1. He is left-handed.

2. He is right-handed.
3. He is ambidextrous.

These expressions are grammatically correct and commonly used to describe someone's hand dominance. "Left-handed" means someone primarily uses their left hand for tasks, "right-handed" means someone primarily uses their right hand, and "ambidextrous" means someone is capable of using both hands equally well.

4. He is a right-handed person.
5. He is a left-handed person.
6. He is an ambidextrous person.
7. He is an ambidexter.

These expressions are also grammatically correct and convey the same meaning as the previous set of expressions. The terms "right-handed person," "left-handed person," "ambidextrous person," and "ambidexter" indicate the hand dominance of an individual.

8. Look at the guy!

In this sentence, "the guy" can be interpreted as referring to either a male or a female. While "guy" is commonly used to refer to males, it can also be used in a more general sense to refer to individuals of any gender. It has become a gender-neutral term in informal or colloquial usage.

9. You guys are working very hard at the workplace.

This sentence is correct. "You guys" is an informal way of addressing a group of people, and it is understood to include both males and females. The term "guys" has evolved to encompass all genders when referencing a group. The preposition "at" is the correct choice in this sentence, indicating the location of the hard work being done by the group.