I can't - it turned out to be huge (7)
I believe the answer is:
titanic
'be huge' is the definition.
(I've seen this before)
'i can't it turned out' is the wordplay.
'turned out' indicates an anagram (turn out can mean to organise).
'i'+'cant'+'it'='icantit'
'icantit' is an anagram of 'TITANIC'.
'to' acts as a link.
(Other definitions for titanic that I've seen before include "Colossal, liner" , "like Oceanus" , "Gigantic like doomed ocean liner" , "Very big and powerful" , "Of great force or power, like the ill-fated ship" .)