Correct spelling, explanation: the correct form is good afternoon. This phrase is a standard greeting used when meeting or greeting someone during the afternoon hours. It is considered a polite and appropriate greeting. Goodafternoon is not a recognized or commonly used word in English.

Definition of good afternoon:
exclamation, expressing good wishes on meeting or parting in the afternoon.
As I entered the office, I greeted my colleagues with a warm smile and said, “Good afternoon, everyone!”.
The host of the event stepped up to the podium and addressed the audience, “Ladies and gentlemen, I would like to extend a warm welcome and wish you all a good afternoon”.

Collocations with good afternoon:
Some most commonly used collocations include:
1. Say/wish/greet someone good afternoon: used when extending a greeting or well wishes to someone during the afternoon.
I walked by my neighbor’s house and waved, saying, „Good afternoon, John!”.
2. Have a good afternoon: expressing the hope or desire for someone to have a pleasant or enjoyable afternoon.
Before parting ways, she smiled and said, „Have a good afternoon!”.
3. Enjoy a good afternoon: suggesting that someone should make the most of their afternoon and find enjoyment in their activities.
The park offers a serene atmosphere where you can relax and enjoy a good afternoon.
4. Spend/have a good afternoon together: referring to spending time in each other’s company during the afternoon.
Let’s meet up for coffee and spend a good afternoon catching up.

Incorrect spelling, explanation: the reason you cannot spell goodafternoon as a single word is that it is not a recognized or commonly used word in the English language. In English, good afternoon is traditionally written as two separate words. You shouldn’t change that rule, therefore the only correct spelling is good afternoon.

Incorrect spelling

Incorrect spelling

Incorrect spelling