Struggle avoided periodically (3)
I believe the answer is:
vie
'struggle' is the definition.
(to vie is to struggle or contend with)
'avoided periodically' is the wordplay.
'periodically' means one should take alternating letters (letters must be selected 'every so often').
The alternating letters of 'avoided' are 'VIE'.
(Other definitions for vie that I've seen before include "I've got to contend" , "Strive in French way?" , "Compete (with others)" , "Eagerly compete" , "Try to do better than" .)