I hate this term because it's so convoluted and pretty much common sense, but here goes.
Implied odds are when a hand has more value than it would seem because of future bets that will be put into the pot after you make your draw. For this reason, It is often correct to call with draws that you are not getting the correct pot odds for because you can extract more chips from your opponents when you hit, and simply fold when you do not. This is most prevalant in no limit and pot limit games where the bet size is much bigger in relation to the pot than in limit games.
Now as the name suggests, Reverse implied odds are the flip side. Reverse implied odds come into play when a hand has less value than it would seem because should an opponent hit their draw, they will be able to get more money from you, but you won't be able to get money from them if they miss. Long story short, If my hand benifits from Implied odds, my opponent is hurt by reverse implied odds.
Example: NLHE Tourney
Player 1 has AsAc, player 2 has AdKd
there are 50 chips in the pot at the flop.
they both have 1000 chips remaining in their stack.
flop is Jd 7d 2c
Player 1 bets 50 chips.
Now, player 2 is roughly 1 in 3 to catch his flush and win this hand. For arguments sake, say he has a very good read on player 1 and knows he has aces. the pot is only laying him 2:1 on making his 3:1 shot so he does not have the pot odds required to make the call. However, he knows that player 1 will not be able to get away from his aces should a 3rd diamond show up on the turn or river, all of a sudden, it's an easy call.
Player 2 has Implied odds to make this call, while player 1's aces Suffer from Reverse Implied Odds. God that's convoluted, let me know if that helps, or confuses you more.