The most common and most likely answer to this crossword clue is the 3 letter word APT
I've seen this crossword clue in The Times
A
P
T
More clues leading to the result APT
- A pint is suitable for the circumstances
- A small part is suitable
- Top class training makes us fit
- Fitting carpet regularly
- Fitting a small part
- Suitable small apartment
- Suitable carpet oddly overlooked
- Suitable physical training after first of August
- Prone or flat in compact form?
- A case for Poirot? That would be appropriate
Buddy explains!

The straight part
We know that "Prone" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case prone = apt.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 APT mean?
APT adjective- Suitable; appropriate; fit or fitted; suited.
- (of persons or things) Having a habitual tendency; habitually liable or likely; disposed towards.
- Ready; especially fitted or qualified (to do something); quick to learn.
- An apartment; a flat.