The most common and most likely answer to this crossword clue is the 5 letter word LONER
I've seen this crossword clue in Financial Times
L
O
N
E
R
More clues leading to the result LONER
- He hates company failure, changing central direction
- Solitary individual, I must bring two sides together
- I won’t mix a drink in large shaker ultimately
- Solitary individual – one making advances, it’s reported
- Unaccompanied chap's sides split by joke?
- Mortgagee, they say, not the man for company
- In general, one remote type who remains aloof
- Hands over an individualist
- Individual in Luxor on vacation is reclusive sort
- Solitary individual city dweller dismissing academic
Buddy explains!

The straight part
We know that "reclusive sort" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reclusive sort = loner.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 LONER mean?
LONER noun- One who is alone, lacking or avoiding the company of others.