The most common and most likely answer to this crossword clue is the 7 letter word FINALLY
F
I
N
A
L
L
Y
Buddy explains!
The straight part
We know that "at the end of the day" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case at the end of the day = finally.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 FINALLY mean?
FINALLY adverb- At the end or conclusion; ultimately.
- (sequence) To finish (with); lastly (in the present).
- (manner) Definitively, comprehensively.