Singular sort of English disease (8)
I believe the answer is:
shingles
'disease' is the definition.
(shingles is a kind of disease)
'singular sort of english' is the wordplay.
'singular' becomes 's' (abbreviation sometimes used in dictionaries).
'sort of' is an anagram indicator.
'english' anagrammed gives 'hingles'.
's'+'hingles'='SHINGLES'
(Other definitions for shingles that I've seen before include "Infection" , "Wooden tiles and painful condition" , "Viral inflammation with rash of painful blisters" , "Painful virus disease or roof tiles" , "Disease related to chicken pox" .)