Separate into portions (6)
I believe the answer is:
divide
'separate into portions' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for divide that I've seen before include "Split into portions" , "Split or separate into parts" , "draw between 13A & 19" , "Partition. separate" , "Saying : '. . . . . . and conquer'" .)