A "dogger" is someone who usually puts someone down. Someone who get's a kick out of roasting somebody on either their apparel, physicalities, or personality.
"Dude, I was talking with Jalyn the other day and I can't believe. Every single time someone walked past, he'd have something to say"
"I know man, dude's such a dogger".
Something that's real messed up, doesn't look right, smell right, or just isn't right at all.
"Man, I walked over to the park yesterday and them playgrounds are too messed up, man. Sh*ts janky."