It's just a play of the word "kills"; Akame kills, slashes, etc. Akame means red eye(s).
OK, Does the two lletter "ga" have any significance? There is another series (kill la kill) where there have been no deaths so far (except for peoples dignity!) with a similar title. but it has "la kill" at the end.
I'm not sure, I'm baffled by its meaning myself. I always interpreted the title as kill or be killed, though as the series went on, I don't think that's accurate. But B214 has the right idea.