I must think about this (3,2,3)
I believe the answer is:
let me see
'i must think about this' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for let me see that I've seen before include "Hm" , "a reflective comment" , "I'm thinking - permit me to visualise" , "Get out of my view" , "I must think about this" .)