The most common and most likely answer to this crossword clue is the 7 letter word DREAMED
I've seen this crossword clue in The Guardian
D
R
E
A
M
E
D
Buddy explains!

The straight part
We know that "Imagined" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case imagined = dreamed.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DREAMED mean?
DREAMED verb- To see imaginary events in one's mind while sleeping.
- To hope, to wish.
- To daydream.
- To envision as an imaginary experience (usually when asleep).
- To consider the possibility (of).