How about concise?
A concise answer can be totally wrong or even poorly explained.
Clear, comprehensive, accurate are words more to the point.
The word "springtime" is one word (and summertime as well), referring to the time of year.
"Backoff" is typically written as one word. However, it can also be written as "back off" if used as a verb in a sentence.
It is one word=)
The word "hairbrush" is typically written as one word, not two.
Well you can, it'd be a spelling error, but you can.
Yes, fingernail is written and spelled as one word.
According to several well-known dictionaries, the term "schoolday" is properly written as two words,school day, not one word.
No
The word "underfund" is typically written as one word.
It is usually written as one word.
Yes, overcame is written as one word.
It is one word.