The 이 in 생각이 없는 is the subject marker, so while you could get away with saying 생각없는 in speech, it's not entirely grammatically correct, but you probably wouldn't get corrected mid-conversation for it.
You can't write 생각없는. 생각 is a noun, -이 is a subject particle, and 없다 is a verb. So, there should be a space between the subject and verb.
from what I understand, if you put the 이 after the 생각, it becomes subject but if you put them together, they become object 생각이 없는 사람 means "a thoughtless man" 생각없는 사람 means "a man without thought" idk, cmiiw and sorry for my engrish lol
In Korean, number can usually be implied by context, so it's usually not specified unless it's relevant information that can't otherwise be communicated in the sentence. For these sentences without context, singular and plural translations are acceptable.
Does this have the same meaning as in English- a person who doesn't think of others, or does it literally mean someone who doesn't think?
Well, literally, it means "Not thinking person". So yes, it literally means someone who doesn't think.
Is "Person who does not think" THAT wrong? Are there other translations?
How would you translate "...not thinking of a person" then? I thought it was that.