Writer having sly toot collapsed (7)
I believe the answer is:
tolstoy
'writer' is the definition.
(I've seen this before)
'sly toot collapsed' is the wordplay.
'collapsed' indicates anagramming the letters.
'sly'+'toot'='slytoot'
'slytoot' with letters rearranged gives 'TOLSTOY'.
'having' acts as a link.
(Other definitions for tolstoy that I've seen before include "Lost toy belonging to Count Leo, writer" , "Count Leo . . . . . . ., author of 'War and Peace'" , "Author of Anna Karenina, d.1910" , "He wrote Anna Karenina" , "Great Russian author of 'War and Peace'" .)