What are Informal, Nonstandard, and Slang Words?
The status or stylistic labels informal and nonformal as well as colloquial are terms applied to written usage at the lowest level on the scale of formality.
Most often, sometime is one word: He will wash the car sometime.When some is used adjectivally with time to mean a short time, a long time, or an indefinite time, then it should be written as two words: She has not heard from her friend in some time.