Will someone describe risk to me?

Here are the abilities that affect it, fwiw:
Ease the Burden: ARM(50) - Reduces synthesis progress to control risk. Most effective for finished items.
High Return: BSM(50) - Temporarily increases chances of success in proportion to risk. Most effective for finished items.
Comfort Zone: CRP(40) - Temporarily reduces risk. Most effective for materials.
Harmonize: CUL(10) - Reduces risk. Most effective for finished items.
Close Inspection: GLD(30) - Reduces risk of next action. Most effective for decorations.
Flawlessness: WVR(50) - Temporarily prevents increases in risk. Most effective for parts.