Say you have a pathway
A-->B-->C-->D
So your A leads to production of B which leads to production of C which leads to production of D
In feedback inhibition (or a negative feedback loop), the final product of a pathway (in this case, D) will usually inhibit or stop the first step in that pathway. So in this instance, D would do something to stop A-->B from occurring. It could bind A or the enzyme that makes that step occur.
Basically, the end product somehow stops one of the earliest steps in the pathway