The most common and most likely answer to this crossword clue is the 2 plus 3 letter word TO LET
I've seen this crossword clue in The Times
T
O
L
E
T
More clues leading to the result TO LET
- John, wanting a single, is available
- Sign on apartment maybe one removed from gents?
- One abandoning throne, wanting occupation
- Smallest room I put out for rent
- One leaves loo offered for rent
- John does not have one indication of vacancy
- Piece of land round Egypt is available for hire
- Small drink the French consumed with vacant expression?
Buddy explains!

The straight part
We know that "is available" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case is available = to let.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.