The most common and most likely answer to this crossword clue is the 1 plus 5 plus 2 plus 7 letter word A MONTH OF SUNDAYS
I've seen this crossword clue in The Daily Telegraph
A
M
O
N
T
H
O
F
S
U
N
D
A
Y
S
More clues leading to the result A MONTH OF SUNDAYS
- Many thousands of shakes?
- When best wear is continually needed?
- Anonymous fellow hounds my son at work for ages
- An eternity to pray and hymn, you may say
- Snooty humans involved with fad for ages
- Famous shanty Don’s performing for ages
- Many of thousands wandering for a long time
- Dynamo fans shout wildly for extended period
- Mutating many thousands of eons
- Many thousands of moves taking ages
Buddy explains!
The straight part
We know that "ages" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ages = a month of sundays.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.