The most common and most likely answer to this crossword clue is the 7 letter word INSTEAD
I've seen this crossword clue in The Sunday Telegraph
I
N
S
T
E
A
D
More clues leading to the result INSTEAD
- Sin sporting with dodgy date in place of another
- Rather stained pants
- It’s Dean playing as a substitute
- Rather stained potty
- Alternatively, ten said aid sent as I tend to fracture after separation
- Vice means this of sin compounded, brand no longer in use
- Sainted: devilish as an alternative
- Fashionable drink in outskirts of Stroud as an alternative
- As an alternative, detains criminal
- Rather badly stained
Buddy explains!

The straight part
We know that "as an alternative" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case as an alternative = instead.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 INSTEAD mean?
INSTEAD adverb- In the place of something (usually mentioned earlier); as a substitute or alternative.