A hybrid build is the opposite of a pure build.
In a pure build, every stat point is places either in STR or INT>
in a hybrid, you place some stat points both in INT and STR.
For example, if everytime you level you place 1 point into STR and 2 into INT, you are building a hybrid INT.
As for the farming, here is a thread that explains it all
http://www.silkroadforums.com/viewtopic.php?t=29046