The most common and most likely answer to this crossword clue is the 7 letter word LUMINED
L
U
M
I
N
E
D
Buddy explains!
The straight part
We know that "lit up in the old way" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lit up in the old way = lumined.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.