Single chap, bishop with cholera, unfortunately (8)
I believe the answer is:
bachelor
'single chap' is the definition.
(an unmarried man)
'bishop with cholera unfortunately' is the wordplay.
'bishop' becomes 'B' (chess abbreviation).
'with' says to put letters next to each other.
'unfortunately' is an anagram indicator (a bad or unfortunate spelling).
'cholera' anagrammed gives 'achelor'.
'b'+'achelor'='BACHELOR'
(Other definitions for bachelor that I've seen before include "Single person" , "Non-married male" , "Unmarried man (with a degree?)" , "Unmarried person" , "Graduate" .)