The most common and most likely answer to this crossword clue is the 5 letter word SINCE
I've seen this crossword clue in Independent
S
I
N
C
E
More clues leading to the result SINCE
- Seeing that Saint in church
- Lapse before church and after
- Son in church from that time onwards
- Open about leaving from that time on
- Genuine soldiers disappeared after that time
- … because church is weighed down by wickedness
- Church going after evil from that moment
- European Commission is upset about Norway after that time
- Immoral act supported by the church from that time on
- Seeing that old Liverpool player follows Shankly’s tip
Buddy explains!

The straight part
We know that "for a reason" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case for a reason = since.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 SINCE mean?
SINCE adverb- From a specified time in the past.
- From: referring to a period of time ending in the present and defining it by the point in time at which it started, or the period in which its starting point occurred.
- From the time that.
- Because.
- When or that.