Welgedaan is one word.
It is the Dutch word meaning "comfortable".
Homeroom is typically written as one word.
The word "firefighter" is typically written as one word.
Businessmen is often written as one word. It can be two words or even hyphenated
Underdeveloped should be written as one word, not two words or hyphenated. I hope this answered your question. :)
The word "thunderstorm" is one word.
Chess player is written as two words.
Its one word.
one word - homework
Shoebox, one word.
"Pogostick" is typically written as one word.
One word
One word is fine.