Reddit reviews Flat Top Army Cap-Black W32S38E

Most likely. It doesn't need to be a full suit. Personally, I wear mine with a military-style trench coat. (sort of like this.) I have been informed by several independent sources that this looks fine.

It also varies person to person. I would recommend asking someone who has no reason to be nice how it looks. (That is, not your mother, girlfriend or other close relations, more along the lines of brutally honest friends.)

If it doesn't work out for you, you could always try something else.