I copied this for you from another thread:
Reflex refers to something curving away from you, like the ends of a recurve, or reflexed, bow. Deflex means curved towards you. Most recurve bows have a deflexed riser and reflexed limbs. Many newer longbows have reflex/deflex designs, just like a recurve but in lesser amounts. Some argue that a reflex/deflex longbow is really a recurve but I wouldn't dare venture into that argument. Older longbow designs, like Howard Hill fiberglass laminated bows are purely reflexed. Most self bows, after they develop string follow, are purely deflexed.
Many of us interchange R/D with "hybrid", these bows are primarily a longbow (general D-shape, strings to not touch limbs) with characteristics of a recurve- reflexed limbs.
The modified limb design typically adds arrow speed. Most R/D's will not be a perfect "D" when strung, though some current designs occasionally achieve a full D shape. Some guys refuse to call them longbows. I personally love them, but I love true D bows too...in the end a bows a bow, I love em all!