I once worked with a person who was extremely quiet. In the morning I would say “Good morning” to her and if I was fortunate, I would get a quick “Good Morning” followed by a shut door. This person wasn’t rude, although it could be taken that way, she was incredibly quiet, perhaps socially difficult and probably had a very low self esteem. 

Because of this, people found it hard to start any sort of relationship with her. So she wasn’t a friend, but that didn’t make her unfriendly. 
So what is an unfriendly person?

This proverb doesn’t say a quiet person who doesn’t have many friends. Or an isolated person who doesn’t live with or near other people and therefore may may not have many friends. It isn’t based on how many or how little friends the person has at all. 

As illustrated before there are many reasons why someone may not have friends. 

This proverb is very clear that it is talking about an unfriendly person though. 

So when you look up “unfriendly” what do you get? 

You get synonyms such as hostile, disagreeable, misanthropic, antagonistic, aggressive; ill-natured, unpleasant, surly, sour, inimical, unamicable, uncongenial; inhospitable, unneighbourly, unwelcoming, unkind, unsympathetic. 

These are all things we should aim to avoid when around other people, when we talk or think about other people in their presents or not, and by the way we act. 

I guess simply, an unfriendly person is only thinking of themselves, and what they want. 

That would be unfriendly. 

“An unfriendly person pursues selfish ends and against all sound judgment starts quarrels.”

‭‭Proverbs‬ ‭18:1‬ ‭NIV‬‬