The most common and most likely answer to this crossword clue is the 10 letter word YESTERYEAR
I've seen this crossword clue in The Guardian
Y
E
S
T
E
R
Y
E
A
R
More clues leading to the result YESTERYEAR
- I agree: positive response seen in territory in the past
- See Ray tyre changing? That day is gone
- Missing my puzzle in old version of the Listener in days gone by
- Certainly hurry to consume whisky in former days
- In the past ate rye doubly cooked, grabbing seconds
- Agreed with queen after tense revolutionary period in the past
- Scratching head, puzzle over English sensitivity in the past
- Certainly rare, yet tragic past
- Quite rare, yet growing wild in former times
- Yes, tyre crack received attention in the past
Buddy explains!

The straight part
We know that "past" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case past = yesteryear.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 YESTERYEAR mean?
YESTERYEAR noun- Past years; time gone by; yore.
- Last year.