The most common and most likely answer to this crossword clue is the 11 letter word GREY-HAIRED
I've seen this crossword clue in The Guardian
G
R
E
Y
-
H
A
I
R
E
D
Buddy explains!
The straight part
We know that "Apparently old/Apparently old" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case apparently old/apparently old = grey-haired.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 GREY-HAIRED mean?
GREY-HAIRED adjective- Having grey hair.
- (by extension) old, wise, experienced.