Something that's described as low-down is sleazy, like a cheater's low-down tricks for winning every game of poker. If you get the low-down, that means you have the inside scoop. So, if you're playing poker with a low-down cheater, get the low-down so you can outsmart him!
If voters object to one candidate's low-down campaign methods, they'll probably vote for the opponent — or decide not to vote at all. And some basketball fans might complain that pretending to be fouled by another player is a low-down trick, although a common one. You can also use low-down to describe bluesy jazz or to mean "the inside scoop." When you visit an unfamiliar city, you can get the low-down on fun activities from your friend who lives there.