Severe English author (6)
I believe the answer is:
sterne
'author' is the definition.
(Laurence Sterne, 1713 - 1768)
'severe english' is the wordplay.
'severe' becomes 'stern' (I've seen this in another clue).
'english' becomes 'E' (abbreviation).
'stern'+'e'='STERNE'
(Other definitions for sterne that I've seen before include "Laurence ---, novelist; sounds hard" , "Tristram Shandy creator" , "Irish-born novelist (A Sentimental Journey)" , "Laurence ...... wrote ` `Tristram Shandy' '" , "Laurence ..., author of 'Tristram Shandy'" .)