Abstain from (6)
'abstain from' is the definition.
(to eschew something is to avoid it)
This is the entire clue.
(Other definitions for eschew that I've seen before include "Abstain from, shun" , "Shun, spurn" , "'Avoid, stay away from (6)'" , "Steer clear of" , "Avoid or abstain from, food or people" .)